


Undertaken: A Tale of Two Sisters

by thelovelyskelesisters



Category: Undertale (Video Game)
Genre: Character Death, Emotional Hurt/Comfort, Emotional Manipulation, Emotional/Psychological Abuse, Eventual Romance, F/M, Fluff and Angst, Gen, Having A Bad Time, Implied/Referenced Suicide, Medical Trauma, Mental Instability, Minor Character(s), Original Character(s), POV Multiple, Possession, Post-Pacifist Route, Post-Traumatic Stress Disorder - PTSD, Pseudo-Science, Soul Fusion, Stockholm Syndrome, W. D. Gaster Being An Asshole, human magic
Language: English
Status: In-Progress
Published: 2016-05-09
Updated: 2017-04-10
Packaged: 2018-06-07 01:17:16
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 15
Words: 78,338
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/6779137
Author URL: https://archiveofourown.org/users/thelovelyskelesisters/pseuds/thelovelyskelesisters
Summary: <blockquote class="userstuff">
              <p>
  <b>un·der·tak·en</b>
  <br/>
  <i>1. taken upon oneself, as a task, performance, etc.; attempt</i>
  <br/>
  <i>2. to promise, agree, or obligate oneself</i>
</p><p>Twin sisters hiking to the summit of Mt. Ebott in search of answers to their parents’ whereabouts find themselves plummeting into the solitary world of the Post-Pacifist Underground. As the girls grow more fascinated with their new surroundings and the peculiar skeleton brothers they've befriended, they also begin to uncover secrets of the past that were laid to rest when the barrier was shattered a decade ago. Even with the border between worlds wide open, leaving may no longer be an option.</p>
            </blockquote>





	1. The Fallen Sisters

**Author's Note:**

> Hey, thanks for reading our story! We're just two best friends that have been collaborating on fan garbage for 11 years and just so happen to have recently fallen into Undertale Hell together. We write each of these chapters together in a weird blend of both of our uniquely-mediocre writing styles, so we apologize if it gets confusing at times. This experiment in perspective has been completely for the fun of it, but we would love to hear your from you regardless!
> 
> So be sure to drop a comment, kudos, or talk to us on our [Tumblr](http://anundertaleoftwosisters.tumblr.com/), where you can find out much more about Undertaken.

The summit was almost within reach. From this height, Mimi and Aly had a clear view of the scattered villages at the base of the mountain as well as a distant skyline painted with tall skyscrapers that phased in and out of view with the sun’s glare. The hot breeze that occasionally blew through the trees carried the nostalgic scent of summer. The duo had been trekking up the side of the mountain for a few days now, leisurely soaking in the lush green vegetation and breathtaking scenery on the way up. However, this latest venture was quickly coming to an end.

"Sis! I can see the top from here!" Mimi excitedly pointed to the summit. Sweat dripped down the side of her face in beads and strands of her long brown hair stuck to her moistened skin. She wiped away the perspiration near her eyes and readjusted the flower-shaped hairclip hanging loosely from her bangs, but didn’t mind her less than ideal appearance otherwise. This wasn’t the worst she had sweat during this journey. On the first day they decided to scale Mt. Ebott together, the temperature was at an all-time high for the season.

Her sister Aly, a few paces ahead, grinned back at her. "Another mountain conquered. This wasn't so bad, huh?"

"We've had worse." Mimi chuckled tiredly. Now that the top of Mt. Ebott was in sight, she felt the fatigue in her muscles from the long hike. Even though she and Aly were twins - and she was technically the older one - Aly was physically stronger than she was. Aly’s jet black hair was still tied up tightly in a neat ponytail. And while she was sweating a little, there were no other signs of exhaustion. Mimi was sure Aly could have made it to the summit it one day if she were alone. But, no matter what, her sister was always patient with her.

As they walked a little further, Aly pointed curiously to an alcove in the distance. "Hey, look at that."

"Is that a cave?" Mimi squinted to see the opening on the side of the summit.

"Looks like it. Quick detour?" 

"Of course!" Mimi tried to match Aly's adventurous spirit.

 

Once they had reached the peculiar opening, Aly led the way into the cave's entrance with Mimi cautiously following behind her. It was pitch black, so Mimi brought out her flashlight and shined the way in front of them. After walking in darkness for a while, Aly stopped abruptly and threw her backpack to the ground, sitting down beside it. "I don't know about you, but I think this is a good place for a break."

"You’re stopping here?” Mimi huffed. “But we're so close to the top!" Her hands began to talk for her as she threw them around to accentuate her point. She was convinced that Aly was only taking a break for her sake, but she didn't want to keep holding them back like she always felt she did. “Everyone always goes on and on about this place. You know this is where the barrier that separated humans and monsters used to be; aren’t you excited?”

“Of course I am.” Aly reached into her backpack and pulled out a tattered journal. Loose pieces of paper stuck out from every side and its black leather bindings were barely holding together. “There’s nothing quite like planting your feet at the very top of a piece of history. But…” She began to flip through the disheveled pages of the notebook before skimming through one page towards the end with her finger. “Maybe we should just take a second to let it all soak in. Besides, this is where Mom and Dad’s notes end. This may very well be the last place they visited.”

Mimi shined her flashlight over the journal in Aly’s hands after seeing her sister attempting to strain her eyesight in order to read it. Aly thanked her with a smile before she immediately dove back into the journal.

“No problem!” Mimi nodded with a faint giggle. She glanced down to the item Aly was so immersed in. One of the loose inserts was a topographical map of the mountain. It even displayed the location of where the barrier once was that led to the unknown Underground world that existed far below its base.

Silence filled the cave as Aly studied the map along with the last few pages of the journal. It began to kill Mimi. “Aly, about what you said… I know you’re just stopping here because you want me to take a break,” Mimi said, flustered. “Mom and Dad’s notes don’t even say anything else besides directions on how to get to the mountain. They might not have even made it here at all before…” Her voice trailed off.

Neither she nor her sister knew anything of their parents beyond that. In fact, their collective memories of them were spotty. Sometimes it was almost as if they never even had parents at all. But the notes their mother and father had left behind proved otherwise. They had compiled dozens of entries about different locations all around the world, and about varying subjects. Some of their notes were about the wildlife, sometimes about people they’d met, sometimes simply about the weather. None of it made any sense to Mimi and Aly, but that’s precisely why they decided to follow in their footsteps and travel the same paths their parents did. They held out hope that, maybe if they traveled far enough, they’d find answers. And that’s what led them to Mt. Ebott.

“Look, be my guest to keep poking around without me, sis.” Aly waved her off without taking her eyes off the journal. “But don't go overboard, alright? Remember, we’ve got a long trip back down too.”

Mimi wanted to show her that she was capable of continuing. She lit a lantern for Aly and set it on the ground in front of her while she took the flashlight. "I'm going to go a little deeper in. I'll let you know if I find anything interesting. If not, we’ll head back out and get to the peak. Alright?”

Aly gave her a thumbs up and leaned her head back. Maybe she  _was_  just tired after all.

Mimi treaded lightly through the cave, keeping the flashlight steady in one hand and her other on the walls as she walked. The sound of moisture dripping from the parapets reverberated all around her in an almost soothing rhythm. Each step she took clacked and echoed in musical unison with the droplets. _Such a beautiful sound,_ her inner thoughts were entirely wrapped around her barely visible surroundings.

It wasn't long before she came across a patch of light in the distance. It appeared to be some sort of opening in the top of the mountain itself, shining sunlight down into the cavern. 

 _That’s strange,_ Mimi thought to herself as she approached the light. It was getting bright enough to where she didn't even need her flashlight anymore, so she secured it in the pocket of her jeans.

When she reached the source of the light, she craned her neck as high as she could to see an enormous, gaping hole right at the top of the mountain and nothing but a deep blue, cloudless sky beyond it. Light spilled in and illuminated the cavern walls; its stone glistening like diamonds. From the point where she stood, she could also see that the light continued below her as well.

Mimi stepped gingerly to the edge of the cliff she stood on in hopes of seeing what lay beneath their level. As she stood peering down for just a moment, the ground beneath her began to shift. Suddenly, she could feel the rocks weakening underneath her steps. Mimi’s heart fluttered as her mind caught this sensation, however, her body had no time to react before the rocks under her foot gave in from her weight and fell into the abyss below. She tried to steady herself, but slipped with the caving rocks and only barely managed to grab the edge of the cliff with both hands.

 _Oh my god, oh my god._ She panicked, screaming out for Aly as loudly as she could while she tried to pull herself back up. However, her body was already too exhausted from their previous hike to do anything more than continue to hang there.

“Mimi! Where are you?!” Mimi could hear Aly’s startled voice ringing through the cave. Fortunately for Mimi, her sister had heard her call in no time flat as if it were a bodily reflex.

“Aly, please!” Mimi managed to stammer from the edge of the cliff, willing herself to look anywhere but down.

Aly followed the sound of her sister’s voice and slid to her side within moments. The journal was still tucked securely underneath her arm as if she hadn’t even had time to set it down before running to Mimi’s calls. She dropped it beside her and locked both of her sister's arms with hers and began to pull her up.

"I've got you, sis." Aly reassured Mimi as she tried to plant her legs firmly to the ground to gain more leverage to pull her sister up. There wasn't even time to ask Mimi what had happened. 

"I'm sorry, Aly. I'm so, so sorry," Mimi stuttered as she tried her best to fight the tears away. Her panic was beginning to get the best of her at this point.

"It's okay, I've got you," Aly repeated as calmly as she could manage in between strained grunts. “I’ve got you. I’ve got you.”

Just as Aly thought she'd found a position to comfortably pull Mimi up, the weight of her dangling sister combined with the slick dampness of the rocks became too much. And with arms still locked, the sisters fell screaming into the abyss below them.

***

Aly awoke to the sweet fragrance of flowers tickling her nose. She could also feel the warmth of the sun shining above her. Was she outside again?

When she opened her eyes, the bright reflection of the golden flowers surrounding her took her by surprise. When her vision finally adjusted, she realized that she was also cradling Mimi tightly in her arms. She sat up in a panic and rested Mimi's head on her lap.

"Mimi!" Aly began to shake her unconscious sister. She noticed a deep gash dripping with blood that had ripped through the fabric of Mimi’s jeans, as well as a few scrapes on her arms and face. As for Aly's own body, all she could feel was a sharp pain in one of her ankle, but no other notable injuries as she quickly examined herself.

Mimi immediately started to come around from Aly's calls. Aly sighed a large breath of relief as she embraced her sister even tighter. "Oh, thank god."

"W-What happened?" Mimi asked dizzily. The more she woke up, the more she began to remember. "Wait, did we fall?!"

Aly nodded. "It looks like it. But..." She looked around at the large patch of golden flowers they sat in. The reflections of gold stretched as far as her vision carried. Piles of rubble that looked as if they were once pillars littered the ground throughout the field. Vines climbed up the side of the cavern walls reaching towards the sunlight spilling in. "We were lucky. These flowers broke the fall.”

“What a strange place for flowers—“ Mimi stopped abruptly and flinched at the pain she was finally aware of from her bleeding leg.

Aly was already taking her thin sweater off to wipe the wound and temporarily patch it up. "You must have cut yourself on one of those falling rocks,” she exclaimed as she wrapped the sleeves around the gash. "We have to find you help. Can you walk?"

Mimi nodded and she slowly made her way onto her feet. When Aly tried to do the same, she stumbled. The pain in her ankle was more painful than she originally thought.

"Aly!" Mimi caught her sister before she fell. "You're hurt too."

Aly let out an uneasy chuckle. "I think I just pulled something. No big deal, I promise."

"At least let me help." Mimi wrapped her arms underneath her sister's and propped her up as they began to take a few steps together.

“Wait,” Aly stopped Mimi every couple of paces to lean down and pick up several scattered pieces of paper around the flower patch. “The rest of the journal. Do you see it?”

Mimi looked around and saw a few more scattered sheets, but no trace of the actual notebook. “I’m sorry, I don’t...”

“I guess it’s not important.” Aly surrendered trying to find it as they picked up the remainder of the sheets that they could salvage. One of them was the map of Mt. Ebott and its surrounding areas. However, even that wouldn’t do them much good now that they were no longer on the surface of the mountain. “Between the two of us, we probably have that entire thing memorized by now.”

Mimi smiled gently. “You’re right. As long as we have each other, it’s just as good.”

The sisters had no idea where they were going, but had no choice but to continue forward down the single pathway they could find away from where they had fallen. They kept walking in one direction until the patch of sunlight was almost out of view again and they were back in darkness.

 

The path ahead of them had been completely silent and devoid of any life for the duration of their walk so far. Aly held Mimi's flashlight while Mimi continued to hold her up in return. They found themselves traversing through old ruins of some sort; statues that once stood tall were crumbled and dilapidated. There were also a number of puzzles and traps that now sat there inactive. No signs of life whatsoever.

After what seemed like a long and painful time of dragging themselves along, they finally came across a small house nestled deep within the ruins. It was apparent that it had been abandoned for a long time, but it still gave Aly and Mimi the glimmer of hope they needed to find their way back to the Surface.

The front door was unlocked, as if the previous resident either didn't expect anyone else to come around or just no longer cared. It was dark inside, but from what they could see in the light of the flashlight, the place was well cared for at one point. The entrance opened up to a large staircase leading downwards and two entrances on each wall that led to various parts of the home.

Aly and Mimi stumbled to the left, where they found what used to be a living room. There were empty bookshelves collecting dust that lined almost every wall. On the remaining bare wall was a fireplace with logs of rotten wood still inside. The room was otherwise completely empty. Aly collapsed onto the hard wood floor in relief that they could finally take a break. Mimi slowly sat beside her, carefully avoiding putting pressure on her injured leg.

"Look at us." Aly laughed tiredly. "We're a mess, huh?"

Mimi smiled back at her. "But at least we're together."

"Can't argue with that.”

Mimi lowered her gaze and her smile began to fade. "Aly, I'm so sorry I got us into this." Tears began to swell in the corners of her eyes. "I'm sorry I was so stubborn… I’m sorry I hold you back, I can't ever keep up with you, no matter how hard I try—“

"Stop." Aly interrupted her sternly, placing her reassuring hands at Mimi’s shoulders. "You're all I have in this world. Stop acting like you’re anything but the most important human being I’ve ever met.” Her grip tightened. Aly was never much for showing a lot of emotion, but she never failed to show Mimi the warmth she felt for her, especially when it came to Mimi’s insecurities.

Mimi sniffled as she wiped the tears away with her sleeve. She let out a small, hesitant laugh. "I'm sorry, Aly. I just get so worried because you're all that I have too. I don't want to be left behind one day because I know how capable you are on your own..." she trailed off. Her insecurity was showing again.

"Promise me.” Aly reached down to touch her hand to her sister's. “Promise me right now that you'll stop thinking like that. Promise me that we're always going to be together."

Mimi nodded, feeling the truth in Aly’s words. She took her sisters hand and smiled gratefully. "To the ends of the earth and..." She looked around at their surroundings. "And whatever lies beyond it.”

Aly stirred on Mimi’s last statement in silence for a moment as she kept her gaze fixed on the ceiling. “So this is it, right? The ends of the earth as we know it. We’re… in the Underground.”

“There’s no other explanation for where we’d be otherwise.” Mimi confirmed. The two let go of one another’s hands as they continued to take in their current settings.

In all honesty, Aly was a bit… underwhelmed. She and Mimi had read many history books detailing the Great War between humans and monsters a millennia prior, as well as countless reports that had been released after the barrier between this world and theirs was shattered a mere decade ago. Even in their travels, they had befriended many of the monsters that once called this place their home. The notion of an entire civilization existing for hundreds of years underneath a mountain intrigued humankind as a whole. There was no longer anyone alive that experienced the war and, therefore, no one in particular that harbored ill feelings against monsters. However, the idea of them had always been treated like a forgotten fairy tale; out of sight, out of mind. So to finally stand in their realm… Aly wasn’t quite sure what she was hoping to feel when this day came. She certainly wasn’t planning to accidentally fall into it with an injured ankle and, even worse – an injured sister.

Aly wobbled up to her feet and stretched out her back. "First thing's first: we have to clean that wound of yours." She began to hobble around to each room of the abandoned cottage while Mimi sat patiently waiting. Most of the rooms were just as empty as the living room. She sifted through cupboards of the kitchen and bathroom, but couldn’t find anything. There wasn’t even running water of any kind.

The only room not completely empty looked like it was once a child’s bedroom. There was a twin-sized bed with no sheets, a dresser, and a wardrobe. All of the decorations had been taken otherwise. Aly searched through the drawers of the dresser, only to find that they were empty as well. However, when she opened the wardrobe, she was surprised to find an assortment of dust-covered clothes still in there. There were a variety of different article types in all different colors and sizes. There was, however, one similarity – they were all striped.

Aly sifted through a few of the hanging outfits before she found a sleeveless dress that looked like it would fit Mimi’s petite build easily. However, it was a little more challenging to find something for herself. She looked down disappointingly at her yellow tank top that had been stained with Mimi’s blood while tending to her wound.

_Just a new shirt, that’s all I want._

Tucked near the back was a loose gray long-sleeved shirt with a single navy stripe running across the chest – the same shade as the print on the dress for her sister. Upon pulling the shirt from its hanger and slipping it over her head and tank top, Aly realized that it was entirely too short and stopped just past her torso. She couldn’t help but snort when she looked down and noticed how ridiculous it looked – but at least it covered the bloodstains.

Aly took one more look in the wardrobe for any way to remedy her fashion faux pas and eventually came across a pleaded skirt in the same navy shade. It matched the shirt perfectly, as if it were meant to be worn together. Aly was a sucker for tasteful fashion. However, it was an interest she had to put on hold when she and Mimi decided to leave their old life behind and follow their parents’ notes around the world. Nowadays, it was very rare that she had the opportunity to wear more than the one tank top and pair of ripped shorts that she barely washed.

Against her better judgment and all former practicality, she took a moment to change out of her shorts and into the skirt. It buttoned comfortably around her waist and had a stylish high-low hem that flowed elegantly behind her when she twirled around once in satisfaction. She made sure to remove the sheets of loose notes haphazardly stuffed in the pockets of her denim shorts from earlier and transfer them securely into her new ones.

When Aly returned to the living room, Mimi was still sitting patiently on the floor. She threw the dress across the room in a loose ball towards her.

“It’s something, right?” Aly shrugged. “I couldn’t find anything to actually help, but at least it’ll feel better to be out of those old clothes. The dress will be easier on your wound.”

Mimi snickered as she eyed the outfit Aly had found for herself. “You went all out there, didn’t you, sis?”

“Hey, it doesn’t hurt to change things up a little when we have the chance. And… we may not get this chance again for a while.”

Mimi nodded in agreement as she held up the dress approvingly. “I like where your head is, Aly. Nothing says _‘Look at us, we’re twins!’_ more than matching clothes.” Aly couldn’t help but laugh.

Since the house couldn’t offer them anything more but shelter, Aly and Mimi knew they wouldn’t be able to stay for very much longer. After a couple of hours of rest, Mimi offered to help Aly search through the rest of the house to see if there was anything else they could take before they went on their way again. When they helped one another hobble down the staircase that led to the basement, they discovered that it wasn’t a basement at all. It was another pathway.

With their flashlight illuminating the way again, the sisters eventually reached a large door coated with rust as if it hadn’t been touched for a very long time. And with nowhere to go and no other options left, they used all of their remaining collective strength to push it open together.

 


	2. The Comedian

**Summary for the Chapter:**

> To Mimi's delight and Aly's dismay, the fallen sisters encounter their first monster of the Underground. Something about this is all too familiar.

**Notes for the Chapter:**

> A short chapter for a short skeleton that hardly needs an introduction.  
> Don't forget to check out our fanfic blog on [Tumblr](http://anundertaleoftwosisters.tumblr.com/)!

Crisp winter air pricked at their skin upon exiting the ruins through the door that slammed shut on its own when faced with a gust of harsh wind. Suddenly, Aly and Mimi found themselves at the edge of a snow-kissed forest with nothing but a single pathway lined with towering trees on either side for as far as they could see. There was nowhere to go but forward.

“That looks like an awfully long way to travel…” Mimi muttered to herself, concerned.

Mimi felt Aly embrace her with one arm, not only for support with their injuries, but most likely to also give her some comfort about the seemingly long road ahead. “We’ve had worse… right?”

Mimi smiled warmly at Aly, acknowledging her encouragement regardless of how reluctant she was to actually continue down this path. As the two interlocked arms, they stepped out into the frigid landscape that neither of them had anticipated. On the surface of Mt. Ebott, it was the middle of summer. Even in the ruins they had just navigated, the temperature was mild. This was something new entirely. Luckily, the ill-fitting shirt that Aly had managed to pick out for herself and the leggings she wore under her new skirt would suffice. However, Mimi's sleeveless dress only came down to her knees. She now wore Aly's old sweater for warmth after they'd replaced the wrapping on her leg with ripped pieces of the clothing they had abandoned - its sleeves now patched with large bloodstains. Whoever lived in that cottage within the ruins didn't think to supply the wardrobe with appropriate winter clothing – as if they had never actually stepped foot beyond the gate.

“Sure is cold out here…” Mimi mumbled softly as she could feel her lips turning blue from contact with the cold air. “But I’m sure we’ll find a place to warm up soon.” Even though she was freezing, she managed to keep some pep in her voice.

Mimi was always trying to look on the bright side of things, no matter what obstacles stood in her way. Aly was strong, but Mimi kept her grounded. Aly huddled against her sister while they walked swiftly down the snowy path. As far as they were concerned, the sooner they got out of the forest, the better chance they had at finding warmth. 

After several minutes of walking, it occurred to Mimi and Aly that the path may have been longer than they expected. And that, in their condition, it would be best to try and find a form of shelter as soon as possible, even if that meant making one of their own. "Keep walking down this path," Aly instructed her sister. "I'm going to dig around a bit and pick up some branches for us to make a fire. I'll only be a few steps behind you."

“Are you sure…?” Mimi asked hesitantly, stopping to allow her sister to regain her composure from the lack of stability.

Aly nodded. “I’ll be fine." She gave a quick smile of reassurance. “You’ve seen me through worse.”

Mimi never liked the idea of separating from her sister, but she trusted her. And the thought of being able to sit by a warm fire was the most comforting thought she could gather beyond how cold she was. Mimi nodded in agreement and began to continue forward. “But if you need me, you’d better yell for me!” She teased as she threw her hand in the air, pointing at Aly. She knew her sister was stubborn at times, especially when it came to making sure they were both taken care of.

Aly smirked at her sister as she waved her on. “Yeah, yeah.”

Mimi knew Aly enjoyed taking care of her and providing for the two of them. She felt the same.

 

As Aly began to slow her pace and occasionally walk off of the path to gather fallen branches, Mimi continued forward. Eventually, Aly became a speck in the distance behind her while the view of a bridge formed ahead. She didn't want to leave Aly so far behind, so she resolved to keep walking for now and wait for her once she reached the structure.

Mimi looked around, taking in the beauty of the snowy forest. _No wonder the Underground is so popular in the winter_ _,_ She thought to herself as she recalled her friends on the Surface that always suggested she and Aly take a trip down here for the scenery. _If only we weren’t in this situation, it would be a perfect vacation spot._

By this time, she had reached the bridge. It was definitely an interesting setup. There were towering wood beams around it, resembling something like a fence or gate of some sort. The wood was completely rotten, and yet somehow still stood on its own. However, whoever assembled it hadn’t really thought about the distance between the beams because Mimi could easily slip through. This was amusing to her. She couldn’t help but slip in and out between the beams, giggling every so often at her own silly game.

Suddenly, the hairs on Mimi’s neck stood on end. She felt someone, or _something_ , behind her as if manifesting from thin air. She could hear footsteps crunching against the snow that couldn't have been Aly's. She was still too far away. It took a moment, maybe not even that long, before the footsteps seemed to stop. She wondered if she had maybe lost too much blood. After all, there was no way the footsteps could have approached her so suddenly without her noticing the presence of someone else before.

"Kid...?" A deep voice greeted her hesitantly. It seemed to be addressing her as if it knew her – or at least thought it did. However, she didn't recognize it. Mimi's eyes grew wide from fear. She wasn’t sure what she should do next, but was undoubtedly too afraid to turn around.

"...Don't you know how to greet a new pal?" The voice continued, only slightly more confident this time but still with an undertone of uncertainty.

Mimi stood frozen in place. 

"Turn around...

_...And shake my hand."_

Mimi slowly turned her body to face the stranger.

It was... a skeleton. 

When their eyes met, he immediately retracted his outstretched hand, as if he were more intimidated by her than the other way around. The lights in his eye sockets shrunk to surprised pinpricks.

"O-Oh! You're not..." He trailed off before dragging his hand down his face and letting out a few silent chuckles. "I'm sorry, I thought you were someone else. You look just like— well, uh— I guess I'm just having a bit of déjà vu.”  

Mimi watched with a confused expression as the skeleton continued to fumble over his own words nervously. She and Aly had many monster friends on the Surface, but they had never met any skeletons before. And this one... was very short. He only came to about torso-level on Mimi. Even though she was still skeptical of his motives, she felt her body relax a bit. He didn’t look nearly as intimidating as he sounded. He wore a think blue jacket with a lining of fur on the inside that made him look even smaller, though Mimi wasn't even sure if skeletons were capable of feeling cold.

He stopped mid-ramble and extended his hand out again. "Wow. Uh, hey that was super rude of me. I'm Sans. Sans the skeleton."

Mimi reluctantly accepted his handshake this time. "H-Hello. I'm Mimi and—“ Her eyes glanced over Sans' head to see her sister now sprinting towards them. Her run had a dramatic limp to it because of her ankle, but there was no doubt that Aly was worried about letting Mimi get so far ahead without her and _then_ seeing her in proximity of a strange monster. She had even dropped all of the branches she previously gathered in order to reach them faster. Mimi pointed behind him. "Oh! And here comes my sister.” A wave of relief washed over her as she watched her sister quickly approach them.

Sans spun around to see Aly was now right behind him. "Mimi!" She panted worriedly as she tried to catch her breath. Aly immediately focused her gaze on the stranger standing between her and her sister. "Is everything... alright?"

Mimi nodded. "Oh yes, I'm fine! This is Sans. Sans the skeleton! We, um, just met. By accident, I suppose." Mimi placed her finger on her chin, unsure of how to explain the happenstance.

Aly furrowed her brow as she sized up the small skeleton. "Aly." She introduced herself dryly. Unlike her sister, Aly had a difficult time trusting new people - especially new monsters that she had never encountered before. "And what does _'by accident'_ mean?" Mimi could tell in Aly's voice that she had her guard up.

Sans shrugged. " _Tibia_ honest, I thought your sister was... someone else. An old friend that I haven't seen in a very long time." He shook his head, as if still embarrassed of his actions. A small snicker escaped from Mimi. Aly quickly shot her stern look, hoping he hadn’t heard but he already had. His grin seemed to grow slightly, but he was quickly encapsulated with his previous thoughts as he became aware again of his mistake. "That was really dumb, there was no way it would have been them. But..." His expression grew a bit more serious. "Where did you guys come from? There are no entrances to the Underground from that direction. In fact, you couldn't be farther away from the border in New Home."

"We fell down here," Mimi replied embarrassed, cautiously turning her leg to the side to show Sans the injury she had sustained. "We were climbing the mountain and found an opening at the top. I went adventuring a little too far, Aly tried to save me, and before you know it... we had fallen through."

Sans had all but burst out in laughter. He hunched his shoulders over and covered his face with one hand. 

"What's so funny about that?" Aly growled as she stepped over to Mimi's side. The pain in her ankle had been exacerbated from the running, so she stumbled slightly. Mimi caught her from falling just in time.

"The irony." He could no longer stifle back his amusement. "The border between the Underground and Surface has been wide open for over a decade and humans are still  _falling_  down here."

Mimi could see that Aly's patience was growing thin with Sans. She let out her own little laugh before Aly had the chance to snap back an angry response.

“It’s silly, right?” Mimi agreed. “Crazy, even. But I’m afraid we need help getting back to the Surface now. You said the border is in New Home, right? If you could point us in that direction we’ll be on our way.”

“Not like that you won’t, kid.” Sans pointed to her injured leg. He turned to Aly. “You too, sweetheart. If you’ve got a _bone_ to pick with me, do it when you can walk.” He had definitely picked up on Aly’s hostility towards him. “In the meantime, you’re more than welcome to stay with me and my brother.”

“That’s very kind, but we really can’t stay.” Aly reminded him.

Mimi nodded in agreement with Aly. “Yes, we could never ask you and your brother to take two complete strangers in. Is there a doctor nearby?” She began to look around the landscape once more. “We’ll just stop by there and get these injuries cleaned up.”

“Afraid not, kid.” Sans shrugged nonchalantly again. “If you’re not familiar with the Underground nowadays, it’s not much more than a tourist trap since the barrier was taken down. And this is slow season. Only a few stubborn monsters that didn’t want to deal with adjusting to the Surface are still here. No monster with healing magic in their right mind stayed here when they had the option to expand their practices elsewhere.” He paused a moment, winking at the girls. “So, heh, if I were you, I’d take up my offer to ride those injuries out with us so you can heal faster and get home.”

Mimi glanced at Aly in search of an answer. Even though it was obvious she didn’t enjoy his smug attitude, Aly eventually sighed dejectedly and gave her approval. Neither of them could deny that it would be nice to be able to rest comfortably for the first time since they began scaling the mountain.

“Lead the way then, _funny bones._ ” Aly stepped out of the way and gestured almost sarcastically to the path ahead of them.

Sans grinned. “Oh, just you wait. You guys are in for a skele- _ton_ of fun.”

Mimi couldn’t help but snicker again as Aly shot her another look.


	3. The Captain

**Summary for the Chapter:**

> The sisters arrive in Snowdin and meet the Captain of the Royal Guard.

**Notes for the Chapter:**

> And after this chapter, we are finally done with setup and introductions! Let the bad times roll.  
> As always, find these chapters and more on [Tumblr](http://anundertaleoftwosisters.tumblr.com/).

The trio wasn’t walking for very much longer before they reached the entrance of a small town. Or, at the very least, it had seemed like less of a trek for the sisters as Sans kept their minds off of the cold and pain from their injuries with an incessant string of bad jokes and small talk. On their way, they had passed a series of inactive puzzles and crossed a long wooden bridge that led directly to the outskirts of this new setting. A sign that read, _Welcome to Snowdin_ in large, colorful letters greeted them immediately. Flurries of snow gently landed on the roofs and lampposts sprinkled through the streets. It was quiet as they passed by, with only the conversations of a few citizens and shopkeepers filling the winter air.

A smile crept upon Mimi's lips as she took in the surroundings of the wintery village. “This is such a cute little town!” She exclaimed. Mimi was happily surprised at the quaintness of Snowdin.

“Heh. Glad you like it, kid. Our house isn’t too much farther,” Sans pointed forward as they approached the heart of the town. “And Papyrus should be home in no time, you’ll get to meet him too.”

“So what’s your brother like?” Mimi asked delightedly. She was looking forward to meeting him too after the encounter with the small skeleton had gone so well. ...At least for her. She couldn't speak on behalf of her sister's feelings. “Does he like jokes as much as you?”

“Sure he does, he just doesn’t show it.” Sans grinned smugly. “I think my jokes are definitely his favorite. But you’ll never get the Captain of the Royal Guard to admit that.”

“C-Captain?” Mimi and Aly both uttered in unison as they glanced at each other with intimidated expressions.

Sans was visibly amused with their reactions. “You bet. He’s the most ruthless human-hunter the Underground has ever seen. He’s even got the scars to show it. Consider yourself lucky that capturing humans isn’t something we do anymore. But if I were you two…” The lights in his eyes disappeared as he craned his neck back to glare at them. “I’d stay on his good side.”

The sisters slowed their pace slightly; any comfort in the thought of staying with the brothers began to sink as they second-guessed their decision. Sans noticed this and couldn’t hold back a bellowing guffaw as his grin widened.

“I’m just pulling your leg. My bro’s matured so much, but he’s still the biggest softie I know.” He shot the sisters a reassuring look. “He’ll like you."

A wave of relief washed over the girls. Aly rubbed her temples as if Sans’ jokes were literally giving her a headache, but Mimi couldn’t help but chuckle again. Mimi knew her sister; she always gave off the impression that she had no sense of humor. However, this only stemmed from how protective she was. Oppositely, it barely took any effort at all to make Mimi laugh, no matter who you were. She even made herself laugh constantly at her own poor humor.

“Welp, here we are.” Sans stopped and gestured widely with the entire span of his arms to the house in front of him. It was a considerably large two-story home with beautiful wood paneling on the outside that matched the aesthetic of Snowdin itself. Strangely enough, it was the only residential home on this side of town that sat on its own large plot of land with nothing but tall pine trees surrounding it. It was almost hard to believe that it was still within the city limits.

“This is your house?!” Mimi squealed. “It’s so beautiful!”

“Thanks, kiddo.” Sans nodded proudly as he unlocked the front door. “Paps and I have worked ourselves to the _bone_ on some updates to it in the last few years. Gotta keep ourselves busy somehow.” Mimi felt a giggle try to escape as she locked her sights on Aly, who was rolling her eyes.

They entered the home into a foyer that opened up into a large spacious living area. The space was substantially too large for the minimal furniture they kept. There was a large flat-screen TV mounted to one wall, parallel to a large sofa, coffee table, and simple wooden side tables. On the furthest wall away from them was a large staircase that led to an open loft-style second floor. Visible from the ground floor were two doors equally spaced apart from one another on one wall and a third door tucked on the easternmost wall perpendicular to the iron railing that ran across the entire span of the upstairs area. Straight ahead was the entrance to the kitchen, which looked small in comparison to the rest of the space.

“Make yourselves comfortable.” Sans slipped out of his jacket and kicked off his sneakers, replacing them with a pair of worn pink slippers that sat right beside the door. Mimi and Aly carefully slipped off their shoes as well and pushed them as close to the door as possible to avoid getting too much snow all over the dated patterned carpet.

It didn’t take long for Aly to dive into the large sofa and let out a loud, exhausted groan as she sank into the cushions. Mimi smiled widely at her sister’s relaxation before turning to Sans.

“Um, do you mind if I use your bathroom?” She pointed to her leg, still wrapped haphazardly in the dirty, makeshift cloth. “I should probably clean this up.”

Sans pointed up to the open second floor. “Sure thing, kid. It’s the last door. But let me warn ya now – we’ve downsized it a bit. We uh... never needed to prioritize the bathroom.”

“Then why keep it? I don’t imagine skeletons have much use for a bathroom in the first place.” Aly remarked from the couch as Mimi was already climbing up the stairs gingerly with her injured leg.

Sans shrugged. “Every once in a while we’ll encounter some bold off-season humans that just knock on our door and ask to use a monster’s private bathroom like they own the place. Oh, and Paps likes to pretend that he needs to take showers.”

“Oh my god!” Mimi screamed when she opened the bathroom door. “It’s tiny!” She could barely contain her hilarity at how comically small the bathroom was. It had just enough room for a standing shower in the corner, a toilet, and a pedestal sink with a small rectangular medicine cabinet/mirror combination hanging above it. Mimi could touch from one wall to the other with outstretched arms easily.

“All for show, kid.” Sans called back to her from downstairs.

Mimi didn’t even bother to close the door while she unwrapped the injury on her leg over the toilet. She was afraid that claustrophobia would get the best of her if she did. She flinched as the cotton from the cloth stuck to the mix of fresh and dried blood seeping from the gash and let out an audible yelp when she pulled it off completely.

“Need any help, sis?” She heard Aly call in response to her noise.

“No no, I’ve got it!” Mimi replied hesitantly. She really wasn’t looking forward to the process of cleaning the wound, but knew it had to be done. And after seeing Aly relax into the sofa, she didn’t want to pull her away from that. They had both already been through so much.

Mimi took the nearest hand towel she could reach and ran it under hot water before tenderly grazing it over the open wound. She winced with every single pass of the rag on her skin, trying her hardest not to cry out. When she could no longer take the pain of touching the gash, she leaned over to the medicine cabinet and peeked inside to see if there was any sort of antiseptic. Sure enough, Sans wasn’t lying – the bathroom truly was for aesthetics only. The only things sitting on the shelf of the cabinet were a couple of small bones (to what kind of skeleton they originally belonged to, Mimi didn’t want to know), a bottle of ketchup, and, luckily, an untouched roll of medical tape.

Mimi sighed in relief as she grabbed the tape and began to bandage the entirety of her lower left leg with it. It wasn’t a very large roll to begin with, so she used it sparingly just in case she had to change the wrappings again soon. She placed the rest of the roll back where she found it, quietly giggling to herself about the rest of the cabinet’s contents before closing it and facing her reflection in the mirror once again. She didn’t realize how much of a nest her knotted brunette hair had become and the scrapes on her face from the fall. She pulled out the yellow flower clip still dangling from her tangled bangs and ran it under water before drying it off and holding it in her hands for a moment.

_Those golden flowers._

When Mimi looked back up into her reflection and secured the clip back to its home on her head, she grew more and more repulsed with the rest of her appearance. She resolved to take a shower as soon as possible. However, a quick splash of water on her face and running her fingers to smooth out her hair would have to suffice until…

Suddenly, she heard the front door squeak open and heavy, snow-trodden footsteps enter the house.

“Welcome home, bro.” Sans’ deep voice called out.

“Brother, we have… guests?” The unfamiliar voice hesitated with the door closing behind him. It was of a slightly higher pitch than Sans, with the slightest scratchy intonation of a proper accent.

Mimi tiptoed to the staircase railing and leaned over above the living room to see the ruckus. There was a tall skeleton towering in the front entryway. Mimi quickly covered how mouth in amusement; Aly stood at attention directly in front of him, at least a full foot shorter. It was just like her to be so protective.

The skeleton was dressed from head to toe in a slimming black military uniform embellished with various medals across his torso. From one side of his waist hung a long, sheathed weapon that resembled a sword. But from closer inspection, Mimi could see the end of a very large bone protruding out from where a hilt would normally rest. A red cape-like scarf was draped loosely around his neck and down his shoulders.

“Aly.” Aly introduced herself stiffly with a trembling hand extended out in front of her.

The skeleton examined her with a stern expression before his features fell into a smile as he grabbed her hand gently in both of his and bowed to meet her gaze. “Such a pleasure, Aly. I am The Great Papyrus!”

An instinctive chortle left Aly’s mouth involuntarily. She grabbed her mouth, trying to cover her smile. “ _Great_ , huh?”

“Of course!” Papyrus raised his head proudly. “Not everyone can call themselves the Captain of the Royal Guard!”

“The pleasure is all mine.” Aly was still smiling as she turned in Mimi’s direction and gestured for her to come downstairs. “Well, Papyrus, this is my sister.”

Mimi scurried down the stairs as quickly as her injured leg could take her. She nearly stumbled down the last step as she rushed to her sister’s side. Now that she was on the same level, Papyrus was _much_ taller than she thought. She craned her neck all the way up to see his face. Sans hadn’t lied about his scars. He had several hairline cracks in his skeletal features and a few chips near his eye sockets. If she hadn’t known any better, Papyrus would be terrifying. However, his warm smile proved otherwise.

“Well,” Aly nudged her sister. “Introduce yourself.”

“O-Oh! Right!” Mimi didn’t realize she was too distracted examining his qualities to even say a word. “Hi, Papyrus, I’m Mimi! Aly’s sister.” Mimi paused for a moment. “Wait, she already told you that…” She began to giggle to herself, a bit embarrassed.

Papyrus let out a nasally chuckle under his breath that didn’t quite match his chivalrous diction. “And what do we owe the pleasure of having two lovely humans down here? Season doesn’t start for another few months. I hear it’s actually quite beautiful on the Surface right now.”

“Oh, they’re not tourists,” Sans interjected. “Get this, Paps. They _fell_ down here. From the ruins!”

“Why would you two do such a thing?!” Papyrus’ voice became louder and frantic. “You _are_ aware that there is a perfectly safe and usable entrance in New Home, right? Are you alright? How did you find your way here on your own?”

“Relax, bro.” Sans elbowed his brother at the waist. “I found them in the forest and convinced them to stay with us until their injuries recovered. You could say they… _fell_ for my charm.”

“Sans!” Papyrus groaned as he dragged his hand across his face. His audible distaste for Sans’ joke made Aly laugh again.

To hear Aly laugh was like music to Mimi’s ears. Sure, _she_ knew exactly how to make her sister laugh. But it was a different and rare sensation being able to hear it being drawn out by someone else. Mimi felt like she couldn’t even remember the last time that had happened. The thought that Papyrus might be the one to get her sister smile again had her grinning from ear to ear herself.

“Don’t listen to him, girls. I told you, my jokes are his favorite.” Sans announced with a playful wink directed towards the sisters.

“They are most certainly not!” Papyrus protested, even though he had the faintest smirk on his face.

Mimi shifted her eyes towards Aly, who met her gaze. They both ginned simultaneously having realized their earlier decision was the best possible one they could have made.

“So! Who’s hungry?” Sans clapped his hands together to change the subject. “I’ve got the perfect idea for dinner.”

It hadn’t occurred to Mimi how hungry she really was. She felt her stomach rumbling, demanding nourishment. Neither she nor Aly had eaten since several hours before they fell from the summit of the mountain. All of their remaining food and supplies were probably still sitting right where they left it.

Papyrus let out another groan. “Brother, please don’t suggest what I think you’re going to. You know how much I hate—“

“Yup, I think we’re going to Grillby’s.” Sans interrupted.

“SANS!”

The annoyance in Papyrus’ voice was evident, but watching the skeleton brothers bicker was somewhat amusing for the twins. Both held their mouths shut to keep laughter from escaping. If not for Papyrus’ expression of utter disdain towards Sans, neither would have felt the uncontrollable urge to laugh. Who knew a skeleton was capable of such hilarious facial expressions?

Sans shrugged. “Come on, Paps. Don’t be rude in front of our guests.”

“I’m not the rude one! Maybe _you_ should stop being so rude and ask them what they—“

By this time, Sans had already grabbed his jacket and was walking out the front door. He hadn’t even changed out of his slippers. Papyrus yelled out to his brother again as he chased after him. With no time to react, Mimi and Aly slipped on their shoes and followed behind them, shutting the door to their temporary home behind them.

 

The restaurant was only a few paces west of the brothers’ home. Snowdin wasn’t a large town in any regard, though its emptiness made it feel that way. When they entered, a waft of warm air tingled against Mimi’s face and reverberated through her whole body. The establishment was completely empty with the exception of the bartender, a young female fire monster whose entirety of her physical being was engulfed in dancing green flames underneath her fitted t-shirt and jeans. She looked up with the chime of the opening door and waved.

Sans and Papyrus both gave her a wave back.

“Heya, kiddo,” Sans greeted.

“Good evening, Miss Fuku,” Papyrus politely exclaimed after.

“Well if it isn’t my favorite uncles.” She beamed as she was wiping down the counter of the bar.

“Well, now I just feel like an old pile of bones when you put it that way.” Sans chuckled as he scooted into a booth on the right wall of the restaurant immediately off of the entrance. Papyrus slid in next to his brother as Mimi and Aly took the opposite side together.

Fuku quickly swung around from the bar with a tray of water-filled glasses and attended to their table. Steam sizzled from her hands as the condensation on the sides of the glasses met her wild green flames. However, she didn’t seem to mind it. “And who do we have here?” She pointed her attention towards the side of the booth Mimi and Aly were on. “Visitors?”

“Yeah, something like that,” Sans affirmed, stifling a laugh.

“You two are awfully early for the season,” Fuku addressed the girls.

“Oh, we’re just trying to avoid being set on fire by the summer heat,” Mimi joked happily. However, she immediately regretted it when Fuku raised her brow at the statement. _Flame monster. Right._ She quickly looked down at her lap and felt the blood rushing to her face.

“Hey, nothing wrong with a little fire!” Fuku responded teasingly. “Besides, you humans don’t appreciate how good you have it up there. Meanwhile, I’m stuck down here with these dusty old bones while Dad’s at his new restaurant.”

“Heh, someone has to babysit.” Sans shrugged.

“You’re right. _Me_ babysitting _you_.” She nudged Sans’ arm playfully and gave Papyrus a wink.

“Surely you go up to the Surface every once in a while though…?” Mimi questioned, still feeling embarrassed about her joke.

Fuku leaned on the table casually and smiled at Mimi. “Of course! Don’t be silly, sweetie. We only keep this place open for a few months out of the year. I voluntarily come here in Dad’s place sometimes because—“

“Because Grillby promised Sans he’d keep it open during our guard duty,” Papyrus interjected. “Honestly Fuku, you don’t have to keep catering to my brother’s unhealthy diet year after year.”

The statement made Fuku cover her mouth politely as she laughed before turning to head back to the bar. “Hey, anything for you two. I’ll be right back with a round of the usual.”

The petite flame monster was gone again before anyone had time to respond. Mimi and Aly didn’t even know what “the usual” was and if they would even be able to eat it. However, Mimi was aware that they certainly weren’t the first humans to visit this restaurant, so surely there was some sort of protocol for meals.

“She was nice!” Mimi beamed. Like on the Surface, it seemed that every monster they had encountered so far down here was kind as well.

“Fuku’s the best.” Sans grinned proudly. “She started helping my good friend Grillby out with the family business once they expanded to the Surface and hasn’t complained about it once. She’s really grown into a good kid.”

“And it takes someone truly special to deal with you the way she does.” Papyrus sighed.

“Hey, everyone respects me around here!” Sans folded his arms behind his head. “The perks of being part of the Royal Guard, am I right, bro?”

“ _You_? A royal guardsman?” Aly questioned skeptically.

“You bet, sweetheart. Impressed?”

Aly ignored Sans’ remarks and turned to Papyrus. “Seriously?”

“Well… yes.” Papyrus seemed like he was trying to formulate more of an explanation, but that was all he could muster. “We were sworn into the Guard at the same time when the barrier was opened. Not that we’ve had that much that’s needed guarding in the last ten years.”

“Then why do it?”

“Whether we like to acknowledge it or not, this was our home.” Papyrus folded his gloved hands together on the surface of the table in thought. “Sometimes I cannot understand why anyone would want to remain down here when the Surface is so perfect and the humans have been so welcoming. You should see the house that King Asgore provided us with up there! It has the perfect view of the sunrise. We’ll have to show you when—“ He caught himself digressing into his own daydreams about life on the Surface to humans that were still no more than strangers to the brothers. Papyrus cleared his throat to bring himself back to the original conversation – not that either of the girls minded listening to his excited banter. “Regardless, I’ve sworn to protect these citizens. So for half of the year, Sans and I come back down here to watch over them.”

“What about the other half?” Mimi asked. She made a mental note of his remark about their house above ground.

“That’s what we call ‘the season,’” Papyrus explained. “There’s an influx of human tourists traveling down here during that time. Alphys, er— the King’s Royal Scientist and her lab assistant Undyne take our place in those months. They’re interested in observing the humans’ fascination with this place.”

“Doesn’t really make much sense that the royal guardsmen aren’t around during the Underground’s busiest times.” Aly pointed out. Mimi kicked her sister’s leg underneath the table in a panic. Aly flinched slightly but didn’t even give her twin a glance. Mimi just didn’t want Sans or Papyrus to be offended by Aly’s blunt disposition.

However, neither of them seemed to mind the statement. In fact, they both grinned slightly at one another. “Undyne was the former Captain of the Royal Guard,” Papyrus chuckled. “She taught me everything I know. If anything, she’s more qualified than Sans and I combined.”

“Speak for yourself, Paps.” Sans waved him off. “I’d say my _skull_ duggery has gotten me pretty far as a guardsman.”

Before Papyrus could scold his brother for another incessant pun, Fuku appeared at the edge of the booth again with a large tray holding four plates of identical hamburgers and fries. When the aroma of the food in front of them finally hit Mimi’s nostrils, her stomach tensed up in urgent hunger. Aly wasted no time either. She was already digging into the meal with her hands and stuffing as many fries into her mouth as she could. They were both so desperately hungry at this point that they probably would have eaten dirt if that were what was in front of them.

Luckily, the meal was delicious and well made. As Mimi and Aly continued to shovel food into their mouths without any regard for anything else around them, Sans and Papyrus watched on as they leisurely enjoyed their own plates.

“Oh, and Papyrus?” Mimi asked in between chews of her fries.

“Yes, human?” Papyrus glanced up from his own burger.

Mimi paused, taking a moment to swallow her food completely before speaking once more, “Aly and I would love to see your home on the surface one day!” She gave him a warm smile. “That is, if you both don’t mind of course!”

Hearing Mimi’s statement made Papyrus beam. “Why, yes of course! That would be fantastic!” He laughed in excitement. “And you humans can see the amazing sunrise that we have the pleasure of viewing every morning! It’s quite breathtaking, if I do say so myself.”

Mimi nodded at the taller skeleton while taking bites of her fries. “We look forward to it!” Feeling someone was staring at her, she glanced over to the smaller skeleton brother who was watching her intently. “I-Is that alright with you, Sans?”

Sans nodded, surprised he had been caught, “Uh… yeah, sure.” He quickly grabbed a bottle of ketchup and squirted some all over his plate. “Whatever makes ol’ Paps here happy.”

Mimi smiled, noticing he never glanced away. She wasn’t sure why, but she shrugged it off regardless. Mimi gently nudged Aly, who was halfway through her plate by now. Aly nodded in affirmation at Mimi’s statement and the two sisters went back to focusing on their separate meals.

With that, the four of them continued the rest of their outing in content silence.


	4. The Familiarity of Kindness

**Summary for the Chapter:**

> Mimi starts to develop feelings for Sans. However, Sans can't quite shake the past just yet. She is a waking reminder of _them_.

**Notes for the Chapter:**

> So we lied about the bad times coming just yet. Take some Sans/Mimi fluff to pad the blow. (Or make the bad times hurt more later?)  
> Originally posted on [Tumblr](http://anundertaleoftwosisters.tumblr.com/).

The days were starting to run together. Aches and sore spots in all of Mimi’s joints could affirm that she had been confined to the brothers’ couch for far too long while her wounded leg healed. How long had it even been now since she and Aly first arrived? A week, maybe? Regardless of how much time had really passed, Sans and Papyrus had been extremely hospitable for the entire duration of their stay. Every morning, they’d wake up to breakfast already made by Papyrus before he left on his daily patrol. And after Aly’s sprained ankle healed, she began to take strolls around the town to fend off her own impending boredom. It was during these times that Sans would stay behind and keep Mimi company. He’d sit on the couch with her, watch TV, throw a couple of jokes her way that would have her in side-splitting laughter, and even help her clean the wound when Aly couldn’t stomach it.

_This_ must have been what home felt like. Without their parents around, the girls often felt that home was never really home. Aside from their nanny who looked after them until they were sixteen, the girls had no family but each other. Being with the skeleton brothers was very refreshing to Mimi for that reason.

However, regardless of how grateful she was for everyone’s help, Mimi was also a bit jealous of the luxury of walking that Aly had regained. Even just being able to hobble into the kitchen where she often heard Aly and Sans conversing dryly to one another would have been better than her current state.

“It has to feel a little better by now, right?” Mimi exclaimed to no one in particular. She stared at the wounded appendage as she shifted her straightened leg off of the couch cushions and onto the ground, but it was a fruitless attempt. Needles shot through her leg the moment her foot met the floor. She let out an instinctive whimper, just audible enough to call attention to herself.

As Mimi anticipated, Aly shot her head around the kitchen entryway. Her sister was visibly unamused with Mimi’s attempt. “And where do you think _you_ are going in such a hurry, dear sister?” Aly questioned sarcastically.

“Somewhere that’s not on this couch!” Mimi huffed. “I need to get up and go somewhere – _anywhere_. This is torture.” She was finally reaching the peak of cabin fever.

“Mimi, stop.” Aly was no longer joking. “That gash hasn’t closed up yet, you’re going to hurt yourself.”

“I’m _fine_.” Mimi tried to convince her sister. However, she was having a hard enough time convincing herself. The pain jolting through her entire lower body was hard to hide, and as much as she tried, her face contorted into a wincing expression. “I just want… to go for a walk,” she sighed dejectedly as frustrated tears welled in the corners of her eyes.

“Walking starts with standing, kiddo.” Sans had suddenly appeared in the entryway beside Aly now. He had a hopeful grin on his face. “But if you can manage that, then maybe some fresh air wouldn’t hurt ya.”

Aly shot Sans a glare. “Excuse me?”

“Have some faith in your sister, sweetheart.” He waved her off nonchalantly. “If she’s good to walk, I wouldn’t mind showing her around Snowdin a little more.” He shot Mimi a reassuring wink.

“Yeah, I don’t think so.” Aly crossed her arms, visibly appalled that he would even suggest the idea.

“Please, Aly?” Mimi called out, still seated at the edge of the sofa. She knew Aly meant well, but she was going insane. Not only was the thought of being able to go outside enticing enough, but she had wanted to get to know Sans more as well. Even through the unbearable dullness of spending entire days in one position on the couch, he had been finding many ways to make her laugh and keep her entertained. He always knew exactly what to say.

Mimi gave her sister her best pair of sad puppy eyes, hands clasped together, begging for her permission. It only took a moment for Aly to concede to them with an annoyed sigh. “Only if you’re positive you can walk.”

“Easy!” Whipping the tears from her eyes with a few shakes of her head, Mimi’s newfound spirit was soon challenged as she pushed herself to her feet and felt the needles shoot up even higher. She stumbled, but caught herself on the arm of the couch. She could feel the vibrations of her entire body shaking as her weak legs struggled to support her weight.

Sans and Aly rushed to her side and helped her stand up straight. After a few moments, the sharp pain began to slowly subside.

_I’ve got this_ , she thought to herself as she began to take one step after another. “See?” She let out a large breath, both in exhaustion and happiness. “I’m good!”

“Barely,” Aly muttered skeptically as she watched Mimi pace around the living room slowly like a baby deer.

“It still counts!” Mimi was actually quite proud of herself as she made her way to the door and began to slip her shoes on without actually bending down to reach them. Standing up straight was an accomplishment that she didn’t want to jeopardize. “Okay, I’m ready!” She announced excitedly.

“Forgetting something there, kid?” Sans smirked as Aly dragged her face in her hand.

“Um…?”

“You really _have_ been inside for too long.” Aly shook her head. “Or did you forget that it perpetually snows in a town where _Snow_ is literally in the name?”

“O-Oh that’s right…” Mimi was stopped in her tracks. She hadn’t left the house at all since their first night in Snowdin and had completely disregarded the implications of snow. She looked down disappointingly at the sleeveless striped dress she continued to wear from the house in the ruins. It was a simple, practical find that really suited her. However, Mimi still hadn’t been able to acquire any clothing appropriate for the winter weather.

“Here.” Sans let out a low chuckle as he took his own blue hoodie off and handed it to Mimi. “Warmed it up and everything for ya.”

Mimi felt her face flush as she reluctantly took his hoodie. Darting her eyes at Aly for an answer, her sister motioned for her to take the jacket. She slipped it around her and flipped the fur-lined hood over her head. It _was_ warm, and it fit her perfectly despite the size difference between them. “T-Thank you, but what about you?”

“What? You think I only have one outfit?” Sans shuffled over to the closet in the entryway. It opened up to complete emptiness with the exception of one lone black jacket hanging to the side. It was essentially the same exact design as the one Mimi now wore, but looked newer and a bit more padded for the wintry mix outside. On the left sleeve was an armband with the same insignia that decorated Papyrus’ uniforms.

“Huh, I guess I should have offered you this one.” Sans rubbed the back of his neck uneasily. “What a _bonehead_ , am I right?”

Mimi giggled as she shook her head. “No…” She could feel his resonant warmth still lingering in the lining of the worn blue hoodie. “This one is perfect.”

Sans’ own face began to flush a faint blue as he quickly slipped on his own jacket and shoes. “W-Well good. This one was my makeshift Royal Guard uniform from back in the day, courtesy of Paps. You’re probably better off with that one anyway – this one smells like ketchup.”

Confused by the statement, Mimi curiously held the collar of the jacket she wore up to her nose to find that the one she had actually _reeked_ of ketchup – maybe even more so than the newer jacket did. However, she had no complaints. To her, the scent gave it more character. More importantly, it reminded her of him. Mimi couldn’t help but let out another laugh as they exited through the front door. As she closed the door behind them, she noticed that even Aly had let the slightest grin surface too.

They had both been smiling a lot lately.

***

The cold air that hit Mimi’s face for the first time in several days was more jarring than she expected. She zipped up the front of Sans’ jacket then pulled the hood strings tightly around her neck as she burrowed her face in its fur. She looked down to her side to see Sans walking patiently beside her as she leaned on his shoulder slightly for balance.

“So, where to first?” Mimi asked.

“Completely up to you, kid. I’m just the crutch.”

Mimi contemplated for a moment. “I think I’d just like to see everything!” Her excitement was evident.

Sans chuckled as he looked up at her. “Heh, that’s an awfully tall order, kiddo. And uh, look who you’re traveling with.”

Mimi smiled. “Nonsense! You’ve been nothing _short_ of helpful lately,” she snickered, covering her mouth with her free hand.

“Hey now, don’t let Aly hear you throwing those puns around. She’ll have my skull on a stick for being a bad influence.”

Mimi, although still smiling, slowed her pace and lowered her hand to her side. “You know, I think Aly really likes you. Well… maybe _like_ isn’t exactly the right word. But she appreciates you. We both do!”

“Thanks, kid.” Sans rubbed the back of his neck again like it was a nervous tick. “It’s been a nice change having you girls around. That house hasn’t been this lively in a long time.”

Mimi’s beaming smile turned into a bashful one as she averted her eyes away from Sans and took in their surroundings instead. Gentle snowflakes landed on every exposed surface and coated everything in a pristine white. Just ahead was a dilapidated building coming up on their right. Its windows were boarded shut and the sign above the door was so rusted that it was unreadable.

“Lots of places here closed up the moment the barrier was shattered,” Sans explained, seeing Mimi’s curious glances. “That used to be the library. Heh, guess they didn’t think anyone smart enough to read would stay down here.”

“That’s… kind of sad.” Mimi said quietly.

Sans shrugged. “It doesn’t have to be. All of these monsters are much happier now with their new lives on the Surface.”

“What about you?” Mimi stopped walking for a moment and looked down at him. “Are you happy?”

The question clearly took Sans by surprise as he stopped mid-step as well. “…Well why wouldn’t I be?”

Mimi closed her eyes as she tried to visualize her thoughts in front of her and piece them into a coherent sentence. “Do you ever just… get that feeling? That feeling when you meet someone a-and they’re just so kind…” She opened her eyes and stared directly into Sans’. “But you can just see it in their eyes. Suddenly, you can see all the pain they’ve seen. And you just have to admire how strong they must be to carry that and still make others around them so happy.”

Sans kept his gaze fixed on hers for several moments before snapping back to reality. “T-That, uh, came out of nowhere, kid…”

Sans’ reaction brought Mimi out of her thoughts and back to the reality of her overly prophetic statement as well. Suddenly, she was drowning in a wave of burning embarrassment. “O-Oh my god. I can’t believe I just said that. T-That was stupid, right? So stupid! Oh my god.” She buried her entire face in her fur hood, tugging the draw strings tighter and hunching her shoulders down.

_Oh my god. Oh my god._ She was still screaming internally. _Why would you say something like that? You barely even_ know _him!_

Mimi could hear Sans laughing from beyond the cave she had made for herself in his hood. Without any notice, he loosened the draw strings, flipping the hood back down and left her flushed red face exposed. “Hey, come on now. It wasn’t stupid.”

Mimi shook her head furiously. “No no, I shouldn’t have assumed something like that. I-I don’t even know you that well and… well I _want_ to, but—“ She quickly caught herself again, feeling the embarrassment crawl back up from her confession once more. She desperately wanted to crawl under a rock and never come out now.

“Hey,” Sans was still laughing. “Relax, kid. That’s what we’re doing now, right? Getting to know each other?”

Mimi took note of the expression on his face, noticing he wasn’t taken aback by her actions. She nodded shyly. “Y-Yeah I guess we are, aren’t we?” With slight relief, she could feel the overwhelming embarrassment subsiding inside her now as her face felt cooler and her muscles relaxed.

Sans, though still chuckling at her reaction, grinned as he offered his shoulder to her once more. When she latched onto it, they continued their walk.

“Oh, and to answer your question,” Sans started. “Of course I’m happy. I’ve got a cool life filled with cool friends and an even cooler brother. What more could a skeleton ask for?”

Still too nervous to say anymore, Mimi silently stirred on Sans’ words as they approached two wood-paneled buildings conjoined in the center by a narrow hallway lit with candlelight from the inside. The sign hanging above the left building read _SHOP_ while the right read _INN._

“Mind if we make a stop?” Sans pointed to the little house-like building on the left. “I just wanna say hi to the owner.”

“Of course not!” Mimi was actually excited to meet someone new since she’d arrived in Snowdin.

A bell dangling from the top of the wooden door announced their entrance. The inside of the building was just as small and wood-clad as its exterior. From behind the shop counter, an elderly rabbit woman in a knitted sweater waved cheerfully.

“Well, well, you’re on your patrol early,” Her delicate voice greeted Sans.

“You’ll be proud of me this time, lady– I actually have something to protect today.” Sans gave Mimi a quick glance that made her blush.

"Really now?" The elderly rabbit hummed. "Is that who we have here?" 

“Hello!” Mimi smiled sweetly at the shopkeeper from behind Sans. “I’m Mimi. It’s nice to meet you!”

The woman smiled back, exposing the tips of her long front teeth beyond her gray fur. “The pleasure is all mine, dear. It’s so refreshing to see a new face around here – especially one that can get _this_ one to do his job every once in a while.” She raised a playful brow in Sans’ direction.

Sans shrugged. “Heh, what can I say? I like to take _Bun_ days off.”

“He’s helped me a lot!” Mimi exclaimed as she stifled back a laugh at the notion that Sans most likely had a pun prepared for every instance. “My sister and I couldn’t be more grateful. We don’t know anything about the Underground.”

“Well, that simply won’t do!” The shopkeeper turned her back to them as she began to prepare something on the counter behind her. After a few short moments, she spun around with two pastries in her hands – cinnamon rolls in the shape of bunnies.

“The first thing you should know about the Underground is that our family makes the best cinnamon buns from Snowdin to New Home.” She handed one to Mimi and one to Sans.

Mimi excitedly scooped it up in her hands. The warmth of the pastry in its paper wrapping radiated against her palms as she admired its adorable attention to detail. “Thank you Miss—” She stopped abruptly realizing she didn’t know the woman’s name.

“You can just call me Bunny, dear.” The rabbit caught Mimi’s reluctance. “Of course, that’s just our family name, but Sans has been calling me that for so long that I’m quite partial to it. I’m rather convinced that it’s more familiar than my real one now.”

“I think it suits ya,” Sans said.

“Oh, you don’t say,” Bunny retaliated sarcastically.

Mimi giggled at their banter as she took a bite from the cinnamon bun in her hands. “O-Oh…” She mumbled with her mouth full, startled with the pastry’s sweetness.

“What’s that face for, kid?” Sans was amused.

“This…” Mimi finally swallowed the remainder of the bite in her mouth. “This is the most incredible thing I’ve ever tasted!” She beamed as she could barely contain her astonishment, evident in the way she was now using large hand motions to speak in place of words.

“I like this one, Sans.” Bunny smiled.

Sans chuckled. “She’s an interesting one, am I right?”

By that time, Mimi had already scarfed down the entire bun. She could hardly control herself from licking her fingers, but upon the realization of her rudeness, looked for another way to clean them. After she wiped her hands clean on the bottom of her dress, she turned to Bunny and bowed her head politely.

“Thank you so much, Miss Bunny!” She had a grin from ear to ear. “That was so delicious. How much do we owe you?”

“Nonsense,” Bunny waved her question away. “That reaction of yours was worth every penny. And here,” She reached behind her once again and pulled another identical bun off of the counter. “One for the road.”

Mimi grabbed it appreciatively. “Thank you… Everyone here has been so nice to us.”

“We monsters have a sixth sense for truly good humans, dear.” Bunny leaned over the counter and patted Mimi’s shoulder tenderly. “Come over anytime and I’ll take care of you. Bring your sister too – I’ve seen her walk by a couple of times but she’s never stopped in.”

At first, Mimi was tempted to ask how she knew Aly was her sister. But the obvious answer quickly hit her. _Twins. Right._ Aside from their hair color, most of their facial features were identical. Instead, she gave Bunny one more polite bow as Sans said his goodbyes as well and they went on their way.

 

Sans carefully helped Mimi over to a nearby wooden bench and gently grabbed her arms to support her as she slid down onto the seat. He sighed contently as he joined her.

Mimi looked down at the cinnamon bun she still held in her hand. “I can’t believe how nice everyone has been. First you and Papyrus, then Fuku, and now Bunny…”

“I have to be honest, kid; it’s hard _not_ to be nice to you.” Sans responded. “It’s something about you. I guess you could say… I’ve got this feeling. You know, that feeling when you meet someone and they’re just so kind—“

Mimi caught on to the fact that he was repeating her words verbatim from earlier. Instinctively, she turned her head away, still mortified as she felt her cheeks flush that familiar red. Sans chuckled lightly at her reaction.

“You know, you weren’t wrong, kid.” Sans exclaimed.

“W-What?”

“What you said earlier… about carrying pain. I guess I was just surprised at how accurate that was. Like maybe you knew something that I didn’t – and that’s not something I’m used to.”

Mimi shook her head contemplatively. “Honestly, I feel like I barely know anything about you, Sans. But that was something I felt immediately.”

“Heh, looks like you’ve got me pegged, kiddo. Guess you know me better than you thought.” Sans folded one arm behind his head and used the other to finally start eating the cinnamon bun in his hand that was undoubtedly cold. Meanwhile, Mimi took the bun in her hand and wrapped it up before gingerly sticking it her jacket pocket.

"You've gotta be more hungry than that," Sans said as he took the last few bites from his pastry.

"I'm saving this one for Aly," Mimi responded. "I'd never forgive myself if I didn't let her taste the best cinnamon bun in the Underground!"

"There you go again," Sans gave her an endearing pat on the shoulder. His fingers were still sticky from the bun. "Thinking of everyone but yourself. You're killin' me."

Mimi shrunk away from him slightly as she lowered her brows in concern. "Is... is it a bad thing...?"

Sans pulled away as well, reading Mimi's body language. However, he kept his warm grin plastered widely on his face. "Not at all. It just... makes me feel like I've already known you for a long time, you know? When, in reality, we're in the same boat."

“Well... is there anything you’d like to know about me…?” Mimi finally asked timidly. "We have to start somewhere."

Sans was visibly taken aback by the question, but did his best to think of a solid response. “Sure, kid. Why were you and your sister climbing to the top of the mountain?”

Mimi wasn’t expecting that kind of question. “W-Well…” She wasn’t entirely sure how to answer. In fact, it was hard to explain why without sounding completely absurd. “Aly and I think Mt. Ebott is the last place our parents might have been. And I guess the short of it is that we were looking for them… and now we’re here.”

“Your parents?” Sans sat up from his relaxed position and listened intently. “What were their names?”

Mimi laughed nervously. “Would you believe me if I told you that I don’t remember? Neither does Aly.” She began fumbling with her fingers. “Sometimes… it feels like they almost didn’t exist. But I know they did. They had to… right?” Mimi felt like she was just trying to convince herself more than anyone at this point. “And they wouldn’t have just abandoned us for no reason. We lived in such a beautiful house outside of the city with our nanny… And Aly and I had such nice things – everything we could have ever wanted. They loved us. I know they loved us… so why is it that I can’t even remember what they looked like?” Just thinking about it was starting to give Mimi a headache.

“Hey, I’m sure they cared for you a lot.” Sans placed a hand on the small of Mimi’s back in comfort. “This mountain’s got a pretty bizarre reputation. Something like that honestly wouldn’t surprise me. Trust me, I’ve got my fair share of spotty memories.”

“R-Really?” Mimi’s eyes widened in surprise.

Sans shrugged. “Would you believe it if I told you I couldn’t remember my parents either? Spooky coincidence, right?”

“Have you ever tried to find them?”

Sans paused. “I gave up a long time ago, kid. Not saying you should do the same, but some things are better left a mystery.” He gave an indifferent motion with his hand.

“I don’t believe that.” Mimi exclaimed sternly. “Not for a second. Anything is possible as long as you don’t give up.”

“Kid…” Sans was now looking at her with the same longing stare he had the moment they first met – the moment when he mistook her for someone else.

“There’s that look again.” Mimi called him out on his wavering expression as he continued to stare at her. “Your friend… they told you the same thing, didn’t they?”

Sans sighed as he covered his face with his hand, his perpetual grin still across his face slightly in amusement. “Are you sure you’re not some sort of mind reader, kiddo?”

Mimi smiled tenderly. “You must have really liked them.”

“Heh, yeah, I did. Everyone here did. I guess that’s why sometimes it feels like I’m constantly doing a double take with you. They would have been around your age if they were here.”

“What… what happened to them?” Mimi asked warily.

“It’s kind of hard to explain,” Sans replied.

“I’ve got all the time in the world.” Mimi gazed warmly at him, hoping she was reassuring.

A small blush crept across Sans’ cheekbones. “I appreciate it, kid. But maybe for another time...” He trailed off. “We should probably get you back before that leg of yours freezes to the point of  _snow_ return."

“R-Right!” Mimi was barely aware of how cold her exposed lower body was beyond the pain still lingering in her leg. “I’ll invest in some new pants once this stupid thing is healed. Maybe a new jacket too so I can give this back.” She pulled at the sleeve of his blue hoodie.

“Keep it,” Sans insisted as he stood up and helped Mimi to her feet as well. “I should really get into the habit of wearing this one anyway. Paps went through all the trouble of making sure I had a uniquely-me, uniquely-lazy Royal Guard uniform. So this is the least I could do to make the both of you happy.” He gave her a wink.

Mimi could feel the blood rushing to her face again. A tiny smile graced her lips as she took his shoulder. During their walk back home, she couldn’t help but reminisce about all of the things she had been able to experience with Sans so far. Of course, lazing around on the couch and learning how to tell terrible jokes didn’t seem like much to anyone – Aly especially. However, it was difficult to find words to describe the new feelings stirring in Mimi’s bones.

Other than Sans’ obvious dodge at talking about Mimi’s mystery lookalike, this day had been icing on the cake - solidifying those feelings into something nearly tangible as if Mimi could reach into her soul and grab it. She made sure to take a mental note of that particular conversation because pushing him was the last thing she wanted to do. As she nestled deeper into the blue hoodie, she felt the butterflies in her stomach every time a new memory of him arose.

_This_ was what home felt like.


	5. The Man Who Speaks in Hands

**Summary for the Chapter:**

> Aly bonds with Papyrus. Mimi develops a fever. The River Person offers Aly a ferry ride and suggests that they may find a doctor for Mimi after all.

**Notes for the Chapter:**

> Thank you so much to everyone that joined us for the release of our first five chapters this week! We appreciate everyone that has read this so far and all of the kind words of encouragement we've received. For as long as we remain able, new chapters will now be released _every Thursday!_ Thanks again. Now the bad times _really_ begin.  
>  Originally posted on [Tumblr](http://anundertaleoftwosisters.tumblr.com/).

The smell of something burning interrupted Aly’s dreams.

When she blinked her eyes open, her surroundings were still dark. However, light and the noise of pans clattering spilled from the kitchen. Of course, the burning smell was also stronger now that she was awake.

Aly sat up from her makeshift bed on the living room floor and stretched her limbs, bones in her back popping in the process. Mimi was still fast asleep on the couch with her bandaged leg dangling off the edge and her open mouth emitting fairly quiet snores.

“Never make it easy, do you, sis?” The sight made Aly laugh tiredly under her breath as she pushed herself off the ground and swung her sister’s leg back onto the couch. Even when she fluffed a pillow underneath it and covered it with the blanket, Mimi remained completely out.

Upon closer inspection, she noticed the sweat dripping from Mimi’s face and saturating the pillow underneath her head. When Aly put a hand to her forehead, it was alarmingly warm.

 _A fever_. Aly just hoped that Mimi would be able to sleep it off. After all, there didn’t seem to be anything that could wake her. Mimi had always been the heaviest sleeper she had ever known.

Aly groggily dragged her feet towards the source of the light. She stopped in the doorway to find a certain tall skeleton tending to multiple frying pans on the kitchen stove. He was already dressed in his uniform with his sleeves rolled up and an apron protecting the front of it.

“Good morning, Papyrus.” Aly yawned.

Papyrus jumped slightly as he looked up from the stove and finally noticed Aly leaning against the entryway. “Oh! Good morning, Aly. I didn’t wake you, did I?”

“Something smelled too good to stay asleep.” Of course, she was lying. But Papyrus seemed too invested in his cooking for her to tell the truth.

“That has to be a lie.” He caught on immediately. “I got distracted and burned the toast earlier. Now that’s all I can smell.”

Aly chuckled nervously. “Okay, you got me. That’s what I smelled, too.”

“I’m sorry,” Papyrus apologized. “But I promise the rest of breakfast is going to be great – _almost_ as great as The Great Papyrus!”

Aly snickered as she slouched into a chair at the small kitchen table and continued to watch Papyrus cook. “I didn’t know you woke up this early to cook for everyone. It’s still dark out.”

“Sleep is hardly necessary for us. So I’ve always had plenty of time to cook something before I leave for my daily patrol. I’m afraid if I didn’t, Sans wouldn’t eat anything but ketchup.”

“Not necessary? But I feel like I’ve seen Sans asleep more times than I’ve seen him awake.”

“Well… don’t try to convince him that sleep isn’t necessary. Sometimes I feel like ‘sleeping’ is his way of getting out of doing anything productive.”

“You two are very different for being brothers.”

Papyrus looked up for a moment in thought before looking back down at the stove. “You and Mimi are very different for being sisters. Twins, even.”

“Can’t argue with that.” That statement couldn’t have been more true. Aly and Mimi were polar opposites in almost every way. And yet they were inseparable. “I think it’s better that way. Opposites attract, right?”

Papyrus scrunched his face at her. “Oh my god Aly, don’t imply that I’m attracted to Sans.”

The loudest guffaw slipped from Aly’s mouth before she contained it with her hands as quickly as she could. Stifling back the laughter only made it harder. She felt literal tears welling at the corners of her eyes. “Papyrus!” She could barely speak between gasping laughter.

Papyrus didn’t see the humor in this. He watched on silently while Aly began to compose herself.

“I’m sorry, I’m sorry,” She finally continued. “I didn’t mean it like that at all. I just mean… we get along with opposite personalities, you know? You and Sans, me and Mimi—“

“You and me?” He added.

Aly felt the blood rushing to her face immediately. “E-Exactly. You and me.”

From that point, Aly was too distracted by her own inhibition to notice that Papyrus had finished cooking and already made a plate for her. After he was finished cleaning up and wrapping the remainder of the food for Sans and Mimi to eat later, he sat down across the table from Aly as she shoveled heaping forkfuls of scrambled eggs into her mouth.

“This is delicious,” Aly said with a mouthful of food. She meant it this time. “You know, you’re a really good chef.”

Papyrus’ face lit up at the compliment. “That’s kind of you to say, Aly! I’ve learned so much about cooking and other human hobbies since being able to live on the Surface.”

“You have a house there, right?” Aly politely set her fork down on her now empty plate and turned her attention towards him.

Papyrus could no longer contain his huge grin at the mention of it. “Oh yes! The King was able to relocate us to a very nice home in exchange for our royal services down here. It’s much smaller than this house, but Sans and I don’t need much. The views are priceless.”

Aly lowered her gaze in contemplation as Papyrus continued to revel in the little details of their perfect home. A feeling of sadness began to tighten in her chest. Their home sounded so nice. And Aly could barely remember what her old home looked like. She was… envious.

This was apparently visible when Papyrus stopped mid-sentence and glanced at her. “Aly?”

“Oh! I’m sorry, you didn’t need to stop.” Aly tried to shake the feeling.

“No, it was silly of me to go on and on like that.” Papyrus chuckled uneasily as he stood up and carried Aly’s plate to the sink. “I really should finish getting ready anyway. Would you—“ He paused abruptly. “Would you like to join me? Now that your ankle’s healed, I mean. I’ve wanted to get a second opinion on some new puzzles I’ve calibrated. At least… an opinion that isn’t my brother’s.”

The offer took Aly by surprise. She wasn’t quite prepared to give him an answer. “W-Well I’d love to, but… I think Mimi’s developed a fever. I should really stay and keep an eye on her.”

Papyrus’ expression lowered. “Oh. Y-Yes. You should definitely stay with her. Perhaps another time.”

Before Aly could respond or offer an apology, Papyrus had already excused himself from the kitchen and back up to his bedroom.

 _Smooth, Aly._ She buried her face in her hands for a moment before getting up and returning to the living room. The light of daybreak was now beginning to spill through the windows enough for her to see that Mimi was awake with her eyes just barely open.

“Good morning, sleepyhead.” Aly greeted. Mimi remained silent with her brows raised. This made Aly uneasy.

“H-How long have you been awake?”

“Long enough,” Mimi answered deviously.

Aly blushed as she averted her eyes away from Mimi. “Well, good. Then you should already know that there’s breakfast in the kitchen waiting for you.”

“And _you_ should know that there’s a skeleton in his bedroom waiting on a different answer.”

“You’re delusional.” Aly sighed as she approached Mimi and felt her sweat-drenched forehead again. Still warm. “And I wasn’t lying about the fever. Someone has to watch you.”

Mimi swatted her sister’s hand away. “Oh, you can stop being a mom for one day and spend some time with him. You can tell he was really disappointed.”

Aly couldn’t deny that she felt terrible for turning down Papyrus’ invitation. She enjoyed his company and listening to his stories, but this was all new to her. It was always easier to keep everyone but Mimi at arm's length. That, and her sisterly duties made her feel obligated to stay. “But your fever—“

“Sans will be here, he’ll take care of me.”

“…That hardly makes me feel better, Mimi.” Aly replied flatly. "I'm sure that lazybones is good at fending off boredom, but not a real illness."

Mimi reached over from the couch and pushed her sister with playful force towards the stairs. “Stop stalling. Go!” She gestured a shooing motion.

Aly groaned dejectedly as she hurried up the stairs and stopped at Papyrus’ door. She looked back down the staircase at Mimi, who was giving her a thumbs-up in reassurance.

Aly hesitated before lightly knocking on the door.

“Come in.” Papyrus’ muffled voice beckoned from the other side.

Aly cracked the door just enough to slide in and quietly shut it behind her. Papyrus was sitting on the bed, buckling ironclad gauntlets to his wrists. In the farthest corner from the door were more matching pieces of armor hanging from a mannequin next to a towering bookshelf filled to capacity with literature. Directly in front of Aly was a small computer desk with a closed laptop sitting atop of it and a substantial pile of papers stacked on the edge. The room in general was much bigger than Aly expected.

“H-Hey,” was all she could manage to come up with. _Why is this so hard?_ Her thoughts began tumbling around inside her head.

“Oh! Did you need something?” Papyrus was surprised to find it was Aly again.

 _Just come out with it,_ Aly told herself. “Yeah. On second thought, Mimi will be fine for a few hours. I’d love to join you today.”

“Really?!” Papyrus shot up from the bed in excitement. “That’s great news!”

A wave of relief washed over Aly to find that Papyrus was still just as equally excited about it, even after being rejected the first time. She pointed to his wrists. “So uh… is this something I’m going to need armor for?” She joked.

“No…” Papyrus pondered. “Well, maybe. But probably not! You can borrow mine if necessary.”

Aly giggled. “I think I’ll manage.” She made herself comfortable at the edge of the neatly made bed as she watched Papyrus buckle the rest of the armor tediously over his uniform. He made wearing the suit look so effortless, even though it was undoubtedly twice his weight.

Papyrus stood tall in front of Aly with the suit’s helmet nestled under his arm. He furrowed his brow line slightly as he looked down at her. “Are you… just going to go like that?”

Aly had been so focused on Papyrus from the moment she'd woken up that she had completely forgotten about her sorry appearance. She was still in her borrowed pajamas with her disheveled hair flying in every direction. “R-Right! I guess I need few minutes. But don’t let me keep you from your patrol. I’ll meet you there, alright?”

Papyrus nodded in agreement. “I’ll be just west of the town. I promise it’s easy to find.”

Aly saluted him with one hand as she reached for the door with her other. “You got it, Captain!”

***

Leaving Snowdin had taken Aly a bit longer than she expected. After she got dressed, she couldn’t in all good conscience allow herself to trust Sans with the sole responsibility of caring for Mimi this time. Therefore, she spent some extra time with her sister to make sure she would be comfortable for the next few hours. Aly just hoped Papyrus wasn’t too worried about her whereabouts yet.

The tightly packed snow that crunched under her boots was the only sound out in the unsullied forest. It didn’t matter if anyone had been through here before her; the perpetually falling snow was always quick to cover up any previous signs of life. Sometimes this was a problem. Sometimes, parts of the expanse looked so similar that she couldn’t tell her exact location.

“I should have reached it by now…” Aly breathed into her cupped hands for warmth against the chilly morning air. She had been walking for a while now, and while her surroundings seemed recognizable at first, they were becoming increasingly more unfamiliar the farther she went. She remembered the long and rickety wooden bridge she and Mimi had crossed when they entered Snowdin for the first time from the west. But somehow, she hadn’t encountered that bridge yet. Maybe she had headed the completely wrong way; her sense of direction had been lacking without a compass, or even the sun, to guide her down here.

Aly’s fears were confirmed when the snowy path before her suddenly ended. It was a phenomenon that she had yet to experience in her days of being in the Underground. All she and Mimi had known thus far since exiting the ruins was snow. And for it to stop so abruptly…

Curious, Aly continued down the path that had now become more of a glistening stone texture. The sightlines ahead of her began to grow dimmer, as if the artificial lights of the Underground did not reach these caverns. The air was brisk, but not nearly as gruffly chilling as when the snow was present.

Eventually, the sounds of running water began to echo loudly through the darkness. As Aly continued a few more paces forward, she eventually found herself at the bank of the very river that was the source of the gentle water sounds.

Aly sighed as she collapsed at the edge of the running water. Once the wonder of its soothing rhythm had disappeared, frustration and guilt began to set in.

Her mind wandered back to Papyrus. Hours had passed by now, and she prayed that he wasn’t still waiting for her. However, she knew there were no guarantees in that regard. His dedication is what Aly admired the most about him. And yet, she also admired his work ethic. So maybe, just maybe, he would have seen the fault in waiting this long for her and had instead just gone back to his patrol as scheduled.

 _Please let that be it,_ Aly tried to reassure herself. She felt abnormally guilty for letting him down. _He doesn’t really care_ that _much about me, right?_

That thought just made Aly feel worse.

She really liked Papyrus.

It wasn’t long before Aly was pulled out of her own head by the sound of singing coming from a ways down the river. She craned her head over the edge as far as she could reach and was able to make out the shape of a wooden boat quickly approaching in her direction.

Aly hurriedly staggered to her feet and began to wave the vessel down as the singing grew louder. It was a cheery tune that she did not recognize.

The singing stopped curtly and the boat slowed to a graceful halt as it appeared beside Aly from beyond the dark waters. Its bowsprit was carved in the vague shape of a dog, but the vessel was otherwise very plain. It was being guided by a hunched figure, whose entire body was obscured by a dark cloak.

“Greetings, human,” The figure said in a singsong voice. Their voice was discordant and high-pitched, but Aly still could not identify if they were a male or female. “This is not one of my usual stops.”

“O-Oh, I’m sorry,” Aly faltered. “I’m just a bit lost. If you could just point me back in the direction of Snowdin Town, I’ll be on my way.”

The hooded figure stepped aside to make room for entry onto the boat. “ _Tra la la_ ,” They sung. “That’s the next stop. Come and join me for a ride, _tra la la.”_

Reluctantly, Aly cautiously climbed aboard the small boat and sat down quickly at the fear of losing her balance. “Thank you so much.” She bowed her head in gratefulness.

“Ah, but it is merely the duties of a River Person, Miss Human.”

“Aly,” Aly introduced. “And you are?”

“ _Tra la la. W_ hat’s my name? _”_ The River Person had gone back to singing as the boat began to move again. “…It doesn’t really matter.”

A strange answer, but Aly did not dwell on it. She was just thankful enough for the ride.

 

It seemed like only a few short moments had passed before they were back at the edge of the infinitely snowing forests. The boat was cutting through the river at a swift, yet relaxed pace. Aly sat mostly silent as she listened to the River Person sing and hum various unfamiliar tunes. It put her at ease and made them seem much less intimidating compared to their shadowy, cloaked figure.

“What business does Miss Aly have down here?” They finally addressed her, still singing in between.

Aly’s lackadaisical head shot up at attention from her slouched position – she wasn’t expecting to be spoken to again. “My sister and I are… visiting. But I’m afraid we’ve overstayed our welcome with our hosts and really should be heading home soon. You see, she just injured her leg and can’t quite travel yet—“

“ _Tri li li._ Your sister!” The River Person’s tone shifted even higher. “Seen her in Snowdin with that portly skeleton. Looks just like you. Everyone is taken with her. So kind, so kind…”

Aly nodded, forgetting that the River Person could not see her silent answer. “I swear, she is just too trusting sometimes. That kindness is going to be the death of her one day.”

“ _Tre le le._ Ah, but what a wonderful way to go.”

Aly clenched her fists when she began to think about Mimi. The immediate thoughts of leaving her with a fever began swelling inside as worry sank in. Suddenly, she was more anxious than ever to return to Snowdin. “Excuse me, but… you seem like you know your way around the Underground."

" _Tra la la._ Been here since the beginning," The River Person crooned. "Will be here until the end. The Surface does not interest me."

"Then... you wouldn't happen to know of any doctors around here, would you? My sister, Mimi... her injuries don’t seem to be getting better. I’m afraid we’re wasting precious time by waiting around for something to change.”

The singing cut off abruptly at the question. The boat also began to slow, and Aly realized that they were coming up on a small dock sprinkled with snow. On the horizon, she could see the dim lights and chimney smokestacks of Snowdin.

“This is your stop, Miss Aly.”

Aly stood up once the boat was still and completely docked, but didn’t quite exit yet. “You didn’t answer my question.”

It was silent for a moment before the singing returned. “ _Tra la la. Y_ es I know a doctor. But you should never meet him.”

“…Why not?” Aly frowned. “My sister desperately needs to see him.”

“If that is true, then he will find you. _”_

Aly grimaced at the unhelpful answer and finally stepped off of the boat. It was clear that this was going nowhere. She nodded one more time at the River Person. “Thank you for the ride.”

As she began to walk away from the riverbank, she could hear them singing louder as if still calling out to her, “ _Tra la la. Beware of the man who speaks in hands!”_

***

When Aly arrived back in town, Sans and Papyrus were standing on the front porch of their home. They immediately turned their attention to her when she came into view.

“Aly!” Papyrus called out worriedly.

Aly’s stomach was already in knots from the embarrassment of facing him. “Hey, Paps.” She gave him a pathetically sheepish wave.

“Sans told me that you left shortly after I did, but I never saw you. So I came back here to look for you!” Papyrus leaned down and grabbed Aly’s shoulders anxiously. “Did something happen?!”

“No, it was nothing like that!” Aly squeezed his boney hands on her before gently setting them down. “I’m so sorry, Papyrus. I just got lost. I’m an idiot.”

Papyrus’ expression softened in relief. “You are most certainly not, Aly. And as long as you’re alright, that’s all that matters.”

Aly nodded, thankful he seemed to understand. This was going better than she had anticipated. “I took the ferry back here. The River Person was very entertaining.”

“Heh, that’s _one_ word for it,” Sans chuckled from behind them. “That guy’s a weirdo.”

“They always say the most peculiar things,” Papyrus chimed in. “I once asked them how their day was going, and they responded with something about not wearing enough pants…? What kind of answer is that? How many pants does one monster need?”

“Nothing they say makes sense, bro.” Sans reassured Papyrus. “But hey, when you’re on that river all day, I guess you just gotta _go with the flow_.”

“Honestly, Sans.” Papyrus groaned. “I think I’ve had my fill of your bad jokes for today. I’d better get back to work now that Aly’s safety is confirmed.”

“I’m sorry you had to worry about me,” Aly apologized again.

“I’m sorry I made my puzzles so hard to find!”

Aly smiled. “Hey, maybe that’s a good thing. Maybe that’s _part_ of the puzzle.”

Papyrus’ eyes widened in excitement. “That’s brilliant! In that case, I am NOT sorry they were hard to find!”

As Papyrus turned on his heels and rushed back to his patrol, Sans began to head back inside.

“Wait, Sans,” Aly grabbed the sleeve of his jacket before his arm could reach for the doorknob.

Sans turned to face her. “What’s on your mind, sweetheart?”

Aly wasn’t quite sure what to say, or if Sans was even the right person to say it to. “The River Person. They said something… interesting.”

“Heh, _everything_ they say is pretty interesting.”

“They said they knew of a doctor. For Mimi.”

Sans’ expression wavered. “Did they tell you who this doctor was?”

Aly shook her head. “But does ‘the man who speaks in hands’ ring a bell at all? That was the last thing they said. Maybe that has something to do with it.”

Sans paused pensively. After a moment, his grin returned. “Do you not hear how crazy that sounds? Come on, I thought Mimi was the gullible one.”

Aly sighed. As annoyed as she was with Sans’ mockery, she couldn’t deny that he had a point. Everything the River Person had said _was_ crazy. And she was sure Sans and Papyrus had known this river-riding figure long enough to confirm their nonsensical ramblings to be just that – silly and illogical.

The two of them went back inside and were greeted by a tired Mimi. She was bundled in blankets on the couch with a bowl of soup nestled in her lap.

“How are you feeling, sis?” Aly asked as she shook the snow from her clothing.

“Not so _hot_. But my temperature begs to differ.” Mimi could barely contain her exhausted giggles at her own attempt at a joke.

“Oh. My god.” Aly dragged her hand across her face. “Did you just…”

“Attagirl!” Sans ran over to Mimi’s side and gave her a high-five. “See? Just let the puns flow through ya naturally.”

“I’ve got the best teacher.” Mimi winked.

Aly cringed. “Okay, I’ve realized I can never leave you two alone ever again.”

“Aww come on, your sister is a natural comedy _Sans_ -ation,” Sans held up his open palm again as Mimi giggled and met it for another high-five. Aly groaned as she huddled onto the couch beside her sister. She’d give Sans this one - he always knew how to keep a smile on Mimi’s face. And Mimi’s happiness was enough to distract Aly from all of the constant worries that plagued her mind, if only for just this moment.


	6. The Living Nightmare

**Summary for the Chapter:**

> Mimi's condition continues to worsen. Aly can't escape her recurring nightmares. Everyone is running out of time.

**Notes for the Chapter:**

>  _You're here._  
>  Originally posted on [Tumblr](http://anundertaleoftwosisters.tumblr.com/).

There was nothing but darkness as far as the eye could see.

Aly could barely see her own hands in front of her as she stood in vast caliginosity. Her head was filled with a haggard cloudiness that left her unable to remember how she even ended up in such a place.

 _Where am I…?_  She took a step forward and felt the weight of her foot clack down on a flat surface. With one foot in front of the other, she continued to walk deeper and deeper into nothingness.

Suddenly, the faintest light flickered on in the distance. Aly focused her gaze on it as she continued in the direction she perceived as forward towards the light. However, the closer she approached, the louder an erratic noise began to fill the abyss around her. It was an indescribable reverberation of sounds that made her ears ring.

Unnerved, Aly began to run. The sound continued to echo around her, roaring louder as if it were a beast chasing her. It grew louder and louder until she could no longer move forward.

“Hgh… what is this?!” Aly grabbed her head as the sound split right through her skull. She winced to see the light was still present in the distance. However, she no longer had the will to approach it. The ringing was the only thing that she could focus on.

Even though she had stopped moving forward, the noise grew louder still. It was maddening.

Aly collapsed to her knees as she held her head tightly in between both of her hands in an attempt to block it out. The attempt was fruitless, as if the sound was already ingrained deep within her skull. She wanted to scream, but couldn't even make sense of her own actions beyond the ugly combination of noises. Aly looked up one last time in the direction of the light, only to realize that it was now nowhere to be found. In its place was more darkness; tangible, palpable darkness like waves crashing into her - drowning her. 

She called for help.

 

A voice rang out beyond the ineffable white noise. It was calling out Aly's name.

Aly's upper body shot up from the floor. Instinctively, she gripped her chest as if to prevent her heart from beating out of her ribcage.

"Aly!" Mimi was crouched on her good leg right beside her. "Oh my god, are you okay?" Her eyes were wide with worry.

Aly brought her erratic breathing back to a calm level before allowing a nod toward her sister. "It was... just a bad dream.” A feeling of alleviation washed over her. She didn't know what kind of nightmare it was or what it meant, but Aly was thankful that was all it turned out to be.

“You were shouting,” Mimi explained, voice in a panic. “Shouting out for me.”

“Heh. And here you are, right?” Aly squeezed Mimi’s arm, realizing it was dampened with cold sweat. “Thanks, sis. I knew I could always count on you.” It was nice knowing Mimi was always with her, even in her darkest dreams.

Mimi let out a sigh of relief as she rubbed Aly’s shoulder in comfort before delicately sliding herself back up onto the living room couch. She stretched out her left leg onto a pillow near the other end and grunted quietly as she tried to get comfortable.

“What time is it?” Aly asked, noticing the dim light already spilling through the windows as it always did in the morning.

“Not sure,” Mimi answered quietly. “I think Papyrus is already gone, though. Otherwise, his Royal Guard senses would have gone off after hearing your commotion.”

“And Sans?”

“Still sleeping like a rock, I’m sure.” Mimi giggled tiredly.

Aly stretched her fatigued limbs out before pushing herself off the ground. Upon standing, she realized her head was still throbbing from the incessant noise in her dream. She could still feel the vibrations of it rattling in her skull.

“How are you feeling today?” Aly tried to ignore it by focusing on Mimi.

“Do you want another pun?” Mimi managed to let out another exhausted chuckle as she wiped beads of sweat dripping down her face. “Because I’m sorry to say that I don’t have one that describes how terrible I feel. I’m not as clever as Sans yet.”

“A blessing in disguise,” Aly joked as she touched her hand to Mimi’s forehead. She was startled at how burning hot to the touch Mimi’s skin was beyond the sweat.

“That bad..?” Mimi read Aly’s alarmed expression as she pulled her hand away.

“...Worse than before,” Aly responded. “Have you cleaned your wound recently?”

Mimi shook her head slowly. “It’s... been a couple of days.”

“Then that’s the first order of business.” Aly held her hand out to Mimi and hoisted her up. She wrapped Mimi’s arm over her shoulder to support her as they hobbled up the stairs and into the bathroom at the end of the hallway together, creeping quietly past Sans’ bedroom.

Mimi propped herself up on the edge of the pedestal sink as she rested her leg on top of the commode so that Aly could access the bandages easier.

“I can wake up Sans if you want,” Mimi offered timidly. It was no secret to anyone at this point that Aly had a weak stomach. She had passed the duty of cleaning Mimi’s wound to Sans shortly after the first couple of attempts to do it herself.

“No, he’s already given me enough grief about it. Can’t let him have the satisfaction again.” Aly began to slowly peel the bandages off.

“Honestly, Aly. Sans is a great guy!" She giggled a little, "I think you would like him if you just give him a chance.”

Aly leered. “Sorry, sis. We can’t all be in love with a skeleton like you.”

“Aly!” Mimi leaned over and slapped Aly’s arm, causing her to stop unraveling for a moment. If Mimi’s face weren’t already hot from her fever, Aly was sure it would have been cherry red from embarrassment. “And what about you and Papyrus, huh? What do you call  _that_?!”

“Not the same,” Aly clarified confidently. “I admire his spirit, that’s all.”

“Uh huh.” Mimi smirked back, nudging her sister. “Is _that_ what all that ogling is when he puts on his armor in the morning? Because it looks to me like you’re admiring something else, if you catch my drift.”

“Oh my god, Mimi!” Aly groaned loudly as she returned her sister’s playful slap. Her face began to burn at her sister's comment, but she wasn't about to let Mimi know that.

The two stared at each other intently for a moment before bursting into hysterical laughter. Suddenly, it was like they were thirteen again. The feeling of nostalgia pulsed through Aly’s core and put her at ease. It was a deep sense of contentedness that had been so fleeting for as long as Aly could remember.

Their banter was cut short by Mimi’s fever catching up to her. Her laughter was replaced with a sudden silence as her body began to wobble back and forth.

"Mimi!" Aly's voice bounced off of the tiny bathroom walls as she lunged to catch her sister. "Mimi, are you alright?"

Mimi's eyes fluttered, "Sorry, sis... I'm feeling a bit light-headed..."

“Easy now.” Aly continued to hold onto Mimi tightly, giving her time to regain herself. “Maybe we should hold off on the laughing fits for now.”

Mimi struggled to speak between breaths, “So now you’re telling me... I’m on house arrest  _and_  there’s no fun allowed..?”

“Consult your immune system about that next time it decides it’s going to give up when you need it the most.” After making sure Mimi was steady against the wall, Aly returned her attention to Mimi’s leg. She peeled the remainder of the bandages away gingerly as the swollen skin underneath began to show. Aly stopped before removing the final piece from just over the gash. She already knew it was infected.

“Aly…?”

“Just… give me a second.”

Not only was Aly mentally preparing herself for the task at hand, but she was also cursing to herself over the infection. It was now the most viable explanation of Mimi’s recent temperature. The guilt was lingering in her chest. How could she have let it get this bad?

How could  _Sans_  have let it get this bad?

“Tag out, sweetheart.” That familiar voice exclaimed as if manifesting directly from her thoughts. Sans had appeared in the bathroom doorway, his oddly malleable eye sockets still half-closed from just waking up. “You did the hard part of getting her up the stairs; I’ll take it from here.”

As much as Aly wanted to decline, she stepped aside and let the small skeleton take her place in the crowded bathroom. She had officially lost the tenacity to do this herself.

“Good morning, Sans..!” Mimi greeted him as cheerfully as she could between her hushed voice.

“Mornin’, kid,” He answered endearingly as he removed the last bandage. Mimi winced as the cloth was stripped from the open lesion.

Aly turned her head away, though couldn’t help but steal a glance of the affected area. It was worse than she imagined. The gash that spanned almost the entire length of Mimi’s shin was streaked with a combination of fresh blood and yellow pus. The skin around it was a deep purple that spread into a dark red inflammation encompassing her entire lower leg and, by the looks of the dressing, there had been drainage. It was no wonder Mimi’s ability to walk had declined just as quickly as her fever had developed – it looked extremely painful.

The sight had Aly’s stomach in knots. She leaned her head against the wall and breathed out slowly to exhale the nauseous feeling away. Meanwhile, Mimi’s muscles were tightening from the pain of Sans running over the area with a hot rag. She kept a tense grip on the sink behind her as she gritted her teeth.

“You gotta relax, kiddo,” Sans repeated multiple times in a soft voice every time she reacted to his touch.

“S-Sorry…” Mimi managed to murmur through her teeth.

Aly kept her eyes off the injury and focused on looking Mimi directly in the eyes. She took her sister’s hands off the sink and into her own as she pressed herself against Mimi, bracing for if she felt faint again. It killed her to see Mimi in any sort of pain. “Hey, we’re almost done.”

“W-Why... does this hurt more than before?” Mimi’s voice shook. “I-It’s... supposed to be getting b-better, right?”

It was apparent that Mimi had been avoiding looking at it too, even as Sans was finishing up. Mimi glanced at the wet rag he had used, now soaked red with blood and discharge, and that was enough to make her head reel back in disgust.

Aly squeezed her sister’s hands tighter. “It’s not too bad.” She tried to be reassuring. “You just have to stay off it completely for a little while longer, okay? I think even your sad attempts at hobbling around have been exacerbating it.”

Mimi nodded slowly. “If you think that’s going to be best…”

“I have to agree there, kid,” Sans chimed in. He was already taping the wound into a fresh bandage and cleaning up the mess of the previous one. “Sorry you’ll have to deal with me for even longer too.”

Mimi struggled to let out a weak giggle as she gently swung her leg off the toilet and allowed herself to completely collapse into Aly’s arms, already prepared to support her weight. Aly shifted herself back into a position to be her sister’s crutch as she dragged her back down the stairs and onto the living room couch. All the while, Sans followed behind them with his arms held out and ready for impact – just in case they lost their balance or worse.

Aly fell onto the couch beside her sister. The trip back down the stairs was surprisingly much more difficult than going up.

“You... don’t have to stick around here,” Mimi turned to her. “Sans and I are probably... just going to watch TV or something boring like that...”

Aly had developed a bad habit of leaving her sister recently, if only for a few minutes each day to step outside and get some fresh air. Seeing Mimi’s state now brought forth an onslaught of guilty feelings for not trying to take care of her more thoroughly. Maybe if she had stayed, this wouldn’t have happened.

Aly shook her head. “I think I’m going to take it easy for a while. The least I can do right now is be stuck on this couch with you too.”

Mimi grinned weakly, visibly grateful for that answer. It made the guilt in Aly’s chest waver.

But only for a moment.

***

The darkness had returned.

It was the same smothering darkness as before, Aly had no doubt about that. And when she walked a few paces forward, the same dull light flickered on in the distance. Everything was the same.

So she ran.

The familiar ringing in her ears began, as she anticipated it would, but she refused to stop. The abyss shuddered with noise - a combination of static and grating vibrations slicing through the thick air. Aly could feel her head splitting again, but she continued forward blindly.

 _Don’t stop._   _Whatever you do, don’t stop._

As Aly approached the light, it suddenly felt like an invisible force was pulling her back. It was pushing against her, as if she were now swimming against a current. All at once, her whole body felt weighted down. She was suffocating. Her steps moved like treading through tar. The white noise of the abyss was the only thing that she could focus on. It was as if every force in the world wanted her to stop.

But she refused.

Aly could still see the light. It hadn’t disappeared yet. And that meant it was attainable.

She willed her body to move, one painfully slow step after another. She closed her eyes as she continued to strain every fiber of her being to continue. It should have taken ages for her to reach her destination. Maybe it did and just didn’t feel like it. But when she finally opened her eyes again, there it was – right in front of her.

It was a heart. Dull and gray, yet beating with life. Not like an anatomical human heart, either. Just… a heart. It had such a fragile appearance, as if it were made from glass.

Suddenly, the chaos around Aly disappeared. The abyss was silent except for the rhythmic beating of the heart.

“What…?” Aly hesitantly hovered her hand over it. The light it was emitting was warm.

Before her fingers could graze it, the ground beneath her began to shake violently. It was a rupture so strong that the light of the hovering heart flickered out and Aly was left, once again, in blinding darkness. The invisible weight returned, this time pulling Aly to the ground.

The white noise began to manifest itself again. But this time it was… different. It was a voice, speaking in a garbled language that Aly couldn’t understand. It was repeating the same phrase over and over again, but Aly was no closer to deciphering it with each pass. At this point, she couldn’t even move.

The voice grew louder, angrier. Aly could feel the darkness getting heavier. She was drowning again.

“I... don’t know… what you want!” She yelled into nothingness. The sensation was becoming too much to bear.

The voice snapped back in a series of unsettling reverberations and cracks of static.

Aly called for help.

 

This time, Aly was forcefully jerked awake by the sensation of someone shaking her. Her eyes flew open as she jolted up. It was still dark, but as her vision adjusted and she gained her bearings on her surroundings, she saw Papyrus towering over her with Sans standing behind him. She was slouched on the couch, right where she had fallen asleep next to Mimi. Her sister was beside her, still fast asleep, but with troubled breathing.

“W-What—“ Aly was still trying to shake herself back to reality. Waking up from these dreams left her in confusion.

“You were shouting, Aly.” Papyrus leaned down in front of her and rested his hands on each of her arms. “Are you alright?”

Aly nodded as her heartbeat returned to a normal pace. “Just a dream... Thank you for worrying. You seem to be doing that a lot with me around...”

“We just want to make sure you and Mimi are well cared for during your stay here,” Papyrus smiled warmly at her. “Besides, all that noise was hard to ignore. Sans and I both woke up to it.”

“And Mimi didn’t…?” Aly looked over at her sister in worry. She knew Mimi was an exceptionally heavy sleeper, but that didn’t stop her from waking up to Aly’s bad dreams the night before.

“Doesn’t look like the kid’s doing too well...” Sans stepped to Mimi’s side and moved loose strands of her hair away from her face. “This new bug she’s got is moving fast.”

“An infection,” Aly clarified. A twinge of anger could be heard in her voice. “I guess just cleaning that wound without medicine hasn’t been cutting it.” She could just barely make out the pained expression on Sans’ face when she mentioned it.

“Is there anything else we can do to help, brother?” Papyrus worriedly turned to Mimi as well. “Maybe we should give Doctor Alphys a call—“

“Don’t let the title fool you, bro. She’s a scientist. I don’t think she’s the right person to bother about this,” Sans interjected. “And on top of her busy schedule and the time it takes to travel, it might be a week before she’d even make it here. I don’t know if we have that long...”

“Then… we just keep waiting around?” Aly wasn’t satisfied with his response.

“Got a better idea, sweetheart?”

“Help us get back to the Surface.”

“She’s not going to be able to make the trip like this.”

“Well maybe you should have considered that before you had us waiting around here uselessly in the first place—“

“Enough.” Papyrus firmly interrupted Sans and Aly’s bickering. “This is going nowhere.”

“You’re right, Paps.” Aly stood up and turned towards the front door. “But I’m not going to sit around and wait for something to change any longer.”

Papyrus grabbed Aly’s arm before she could take another step. “Aly, please. It’s the middle of the night. I promise I’ll escort you wherever you want to go in the morning. But please… just try to go back to sleep. You need your rest too.”

Her muscles tensed. Aly wanted to jerk her arm away and argue with him. In that moment, she was so frustrated. She wanted to tell them both that they couldn’t possibly understand how it felt to watch her sister’s condition deteriorate because she spent too long doing nothing. But deep down, she knew that wasn’t fair. Sans and Papyrus had both been trying their best to care for them; putting their own lives on hold for the clumsy humans that fell down a mountain.

Instead of drawing her arm away from Papyrus, she pulled herself closer into him and wrapped her arms around his torso in an embrace. She could feel the vague ridges of his rib cage underneath his t-shirt. It was so uncharacteristic of her, but… nothing else made sense. She was so lost.

After a moment of what was probably surprise at the gesture, she finally felt Papyrus’ arms wrap around her in return.

“I promise things are going to be alright.” Papyrus reassured her.

“Thank you.” Aly fought back tears as let her arms fall back to her sides. “You’re right. You’re… always right. We’ll figure things out tomorrow.”

Papyrus grinned, pleased with the outcome of this conversation. “Try to get some sleep, Aly. I’ll wait for you in the morning.”

As Papyrus headed back upstairs and to his room, Aly noticed that Sans had already left the conversation at some earlier point. However, she didn’t notice him go back up to his bedroom.

Aly stood silent for a moment, wiping away the tears she had fought before. Even though she had full intentions of going back to sleep, her mind was still reeling from her latest dream. She wasn’t ready to return to that hellscape just yet.

Instead, she dragged herself through the dark and into the kitchen. Without turning on any lights, she reached into the cupboard, pulled out a glass, and filled it with water from the sink. Her memory of the kitchen’s layout was a clear indication that she had been staying in this house for far too long.

As she leaned on the counter and drank her beverage, the sound of one of the chairs at the kitchen table scooting across the tile floor startled her.

“Didn’t mean to scare ya,” was all she heard.

Aly didn’t even have to look back. “You have an awfully bad habit of appearing out of nowhere, Sans.”

“Just one of the many magic tricks up my sleeve, sweetheart.”

“You must be one hell of a magician,” Aly sneered as she turned to face him. Her eyes were adjusted just enough to make out the outline of his body, slumped in the seat.

“Heh, what can I say? I’m just such a  _charming_  guy.”

Aly let out a groan as she joined him at the table. “Not going back to sleep either?” She asked.

“Nah,” Sans yawned. “But you should listen to my brother and get some rest. If you hadn’t noticed by now, he cares about you.”

“I’m fine,” Aly answered curtly.

“Mimi will be fine for a few more hours, I promise. If you want, I’ll keep an eye out.”

“It’s… not that.” Aly felt her stomach churning when she recalled the details from her dream. The feeling of her lungs filling up with thick, black air was still too real.

“The dreams, then.” Sans guessed correctly. “The ones you’ve had for the past two nights?”

Aly was unaware that Sans even knew about the first night. Maybe he wasn’t asleep after all. She nodded in wary affirmation.

Sans stood up and approached the kitchen’s light switch. Aly winced when the overhead light flickered on and blinded her for a moment after she had spent so long adjusting her eyesight to the dark. By the time she could open her eyes completely, she noticed Sans was now at the counter, putting on a pot of coffee.

“Mimi said I was calling out to her the first night,” Aly directed her attention back to the nightmare. “What about tonight?”

“Same thing,” Sans responded. “Unfortunately, she was a little out of commission this time. So Paps and I had to answer instead.”

Acknowledging that the brothers had heard her made Aly feel strange, maybe almost violated? She wasn't entirely sure. She wasn’t used to feeling this particularly vulnerable with anyone but Mimi.

A sudden clack onto the kitchen table brought her back to her senses when she realized Sans had already finished the pot of coffee and sat a cup in front of her. "Here, might as well have some of this if you refuse to sleep."

Reluctant at first, Aly took the warm mug and held it in her hands. She stared at her reflection in the dark liquid only to feel like she was suffocating in the darkness that had engulfed her once again.

"Milk?"

"Huh?"

A carton of milk was gently slid next to her. "Thought you might want something to add to that. Dunno how you take your joe."

“T-Thanks.” Aly took the carton and poured a generous amount of milk into the mug, transforming the black liquid into a creamy brown. “…For everything, I mean. Despite the circumstances, Mimi's been... happy. Happier than I think I've seen her in a long time." Aly couldn't bring herself to admit the recent moments that she, too, had felt the same way. Sans was never the one she wanted to confide things in. And yet, he was always the one that seemed to be there at every opportune moment.

“Hey, don’t sweat it, sweetheart.” Sans filled his own mug to the brim with coffee before walking it over to the table and reclaiming his seat. "And don't worry about those nightmares. No one's hurtin' anyone on the Royal Guard's watch."

Most times, Aly forgot that Sans was part of the Guard too. He spent so many of his days around the house with the both of them; it gave her the impression that he was just riding on the back of his brother's success. But, in a way, he was doing his part too - protecting two complete strangers around the clock with no questions asked.

The two of them sat in silence as they sipped from their mugs, stirring on their own thoughts and the occasional small talk until the sun came up. And it was nice, because Mimi was right to see the good nature in Sans that Aly had been refusing to acknowledge all this time.

In more unspoken ways than one, they understood each other.

***

To Sans And Aly's relief, Mimi woke up that morning.

The infection was running its course faster and faster with each passing hour. Her labored breathing grew shallower as the sweat continued to pour off of her pale skin and she could barely sit up long enough without feeling faint.

"G-Good morning..." Mimi managed to murmur as Aly and Sans came into her view. Her words were clouded by a haze of drowsy confusion as she glanced around the room to remember her surroundings.

"Hey, sleepyhead." Aly smiled faintly as she knelt down beside her sister's head resting on the arm of the couch. "How are you feeling?" It was an empty question that she already knew the answer to.

“Like death.” Mimi nodded weakly to Aly before she turned to Sans. "This is some crazy  _femur_  I've come down with, huh?"

Sans stifled back a chortle beyond his worried expression. "How long did that one take ya, kid?"

"I had... a lucid moment in between wanting to pass out... and wanting to vomit all night," Mimi choked out between heavy breathing.

"Alright, alright, I'm banning the human from using skeleton puns from now on." Aly placed her hand on Mimi's forehead and wiped away some of the sweat with her palm.

"If you say so, Fun Police..." Mimi smiled as she reached up and rested her weak hand on Aly's.

"I think you mean  _Pun_  Police," Sans chimed in from behind them.

"Both of you are the worst," Aly sighed. Truth be told, she was just happy to see Mimi smile, no matter the expense.

"But  _you're_  the best," Mimi weakly exclaimed as her grip on Aly's hand tightened. "H-Hey... Are you going to stick around again today? I'd really enjoy that..."

Aly's thoughts immediately shifted to Papyrus. She hadn't slept an ounce, but still intended on going out with him as discussed earlier. Though she really didn't even know what she was going out to look for. Her resolve from last night came in a fit of blind frustration that she couldn't back up with a solid plan. Was she really expecting to miraculously stumble upon the cure for Mimi's illness out there? The futility of the situation was beginning to make a home in her head.

"Of course I'll stay." The choice was easy. It was always easy when it came to her sister.

"I'm... so glad..." Mimi's voice trailed off in exasperation. 

Aly glanced over at Sans as if to pass a secret message to him with just a look. Plans had changed. She was going to stay with Mimi, but she wasn't going to let that mean they were giving up.

Sans received the message clearly. "I, uh... I think I'll join Paps on his patrol today," He fumbled over his words as he tried to think of the right things to say. "Maybe some of the folks in Waterfall can suggest a home brew for the nausea."

"Only... if it's not too much trouble..." Mimi said softly.

"Of course not, kiddo," Sans assured her as he glanced back at Aly, addressing her too. "I won't come back empty-handed."

"Promise..?" Mimi's voice was barely a whisper now.

That single word made Sans’ expression drop, as if the weight of it was overwhelming.

"...Anything for you, kid."

 

The morning came and went. Papyrus and Sans left the sisters to their own devices under the promise of finding a solution to their dilemma. Mimi fell in and out of sleep in between the constant vomiting and faint spells. All the while, Aly stayed glued to Mimi's side, ridden with guilt and exhaustion as the lack of sleep was finally starting to hit her.

This moment was the calm between the storms. Mimi was fast asleep, her injured leg propped up on Aly's lap while the right leg dangled over the edge of the couch like always. Aly was stuck in her current position, but didn't mind. She wasn't planning on leaving Mimi anyway.

The silence in between Mimi's strained snores was lulling Aly closer and closer to the edge of sleep. She held the urge off for as long as she could, but it was winning.

 _Just a little nap._  She told herself.  _Not long enough to go back there. Don't let yourself end up back there, Aly._

Aly wasn't prepared to face the abyss again.

But, then again, the abyss waits for no one.

***

Despite all of her efforts against it, Aly had returned.

Things were slightly different this time. The beating gray heart was already hovering in front of her without her even having to try and reach it. It was as if she were continuing right from where she left off last time.

Aly debated on reaching out for it, recalling what happened before. However, there didn't seem to be any other options.

 _Don't hesitate._  Maybe the outcome would be different if she took a different course of action. It certainly worked last time.

With that notion front and center in her mind, Aly reached for the heart and clasped it firmly in both of her hands. It was _hot._  She could feel the skin on her palms searing and sizzling immediately upon contact. An involuntary scream escaped her, but she still refused to let go. 

"Why..." Aly grunted as she tightened her grip. "Why am I here...?!"

Suddenly, the familiar white noise arose from the depths of the void. It was the same patterns as before: a voice repeating the same undecipherable phrase over and over again.

"I don't know what that means!" Aly cried out through the darkness. She was frustrated. She was in pain. She was desperate.

But, most important of all, she was done playing this game.

With the culmination of all the force she could amass, Aly crushed the beating heart in between her hands, shattering it like glass into thousands of tiny pieces. She grimaced down at her palms that were charred and now embedded with shards of glass.

All noise ceased yet again. It was dark, but the shattered pieces remained hovering in the space around her like dimly lit stars in a solar system. After a moment, they began to tremor with life. The pieces autonomously began to reshape themselves into new forms. One after another, they shifted.

A hand pointing right. A hand with an open palm. A skull and crossbones. A hand with a thumb down.

A bomb. A hand pointing left.

It repeated. Over and over, the pieces cycled through these six symbols. However, it still meant nothing to Aly.

Until, from the depths of her lucid mind, it hit her. Like a derailing train, it hit her hard.

"It's you." Aly's voice shook through the silence. She kept her focus on the symbols flashing by in front of her, still trying to make sense of it. But perhaps maybe she had already figured out enough to get through this night unscathed.

" _The man who speaks in hands_ ," Aly announced into the darkness confidently. "That's you.  _You're here_."

Suddenly the ground beneath her began to rumble again. Her muscles instinctively tensed in anticipation of what would happen next. She was correct to do so as she felt the invisible weight again. The dense air wrapped around her limbs and tugged towards the ground. But she fought it. Aly ground her teeth as she fought to stay standing. 

The voice, wrapped in a blanket of static, was laughing.

Aly could feel the unrelenting darkness pulling even harder now. Eventually, her knees buckled underneath her and she slipped hard onto the cold ground. The heaviness encompassing her entire body made it too difficult to stand back up. Aly felt the fatigue in her bones from fighting so hard; the racing beat of her heart as she panted. Every sensation felt too real for comfort. It was like she was fighting against her own death over and over... and failing every time.

"I'm... n-not...  _afraid of you._ " Aly asserted through her teeth. 

Suddenly, the voice surrounded her. The ringing in her ears returned as it began to speak in coinciding symmetry with the symbols still flashing through the darkness.

**F-I-N-D-**

It was spelling out the message for her.

**M-E-**

As soon as it hissed the final syllable, the air grew denser, toxic. Aly couldn't breathe. Her heart pounded even faster as she began to choke. She thrashed her limbs against the pressure as she tried to escape the miserable sensation.

In between gasps for air, she called for help.

This was worse than previous dreams. It was violent and uncontrollable. Her lungs were on fire from the indescribable sensation that was much worse than drowning.

With her last breath, she called for help.

 

But nobody came.


	7. The Encounter

**Summary for the Chapter:**

> Aly can no longer keep it together. But a strange encounter in Waterfall helps her hold out hope for a little while longer. She's ready to find _him_.

**Notes for the Chapter:**

> Here it is! So, so sorry for the late update! Half of the Undertaken team (aka just Alexa) got sucked into convention season and even [shitty closet cosplay](http://anundertaleoftwosisters.tumblr.com/post/144968397387/catflattery-husbando-and-i-rocking-the) actually requires way more time than she wanted to invest in it. But this chapter has been a labor of love for the last couple of weeks, so we hope you enjoy it! If all goes well, Chapter 8 should still be up as scheduled in order to make up for this. Thanks for everyone's patience!  
> Originally posted on [Tumblr](http://anundertaleoftwosisters.tumblr.com/).

Aly could barely focus on the cup of coffee sitting on the table in front of her. Her vision waned in and out as she blinked hard every few seconds in an effort to stay awake. The restless nights were starting to catch up to her. In between fearing for her life in her dreams and fearing for Mimi’s in the moments when she was awake, it seemed that she wouldn’t be granted peace anytime soon.

Papyrus sat across the kitchen table from her, sipping his own black coffee as he stole occasional glances at Aly and her inability to keep her nodding head up.

“Would you like a refill?” He asked politely.

Aly didn’t even hear him. All outside sounds were being transmitted through a muffled cloud in her brain that dispersed words before she could process them. All she could focus on was  _him_. The man shrouded in darkness, or perhaps was the darkness itself. The man who spoke in hands. The doctor.

In response to Aly’s silence, Papyrus stood up and topped off her half-empty mug anyway. The gesture made her jump back into reality with an involuntarily jerk of the hand that held the mug, pulling it away from the stream of coffee pouring into it from the pot. Waves of steaming black liquid spilled over the top of the cup and onto Aly’s bare hands.

 _“Shit!”_  Aly seethed as she kicked herself up from the table and waved her arms frantically in a trivial attempt to cool the burning sensation. "What is  _wrong_  with you?!" She snapped angrily at the tall skeleton, who was momentarily stunned with her outburst.

“Oh my god!” Papyrus immediately threw the coffee pot down on the table and swung around to Aly. He grabbed both of her hands in his own and wrapped them in the red scarf draped across his neck to dry them of the excess coffee. To Aly’s surprise, this was an effective way to calm the sting that shot through her fingers. The material of Papyrus’ scarf was soft and gentle against her searing skin.

The burning subsided after a painfully embarrassing few minutes like this. Aly eventually took her hands back from Papyrus’ grasp to see the tops were a bright red. The coffee was certainly hot, but not enough to leave any marks. Unfortunately, the same couldn’t be said about Papyrus’ scarf, now blotched with dark brown stains.

Well, that was one way to wake her up.

"T-Thanks," Aly mumbled as she rubbed the needles in her hands away.

“Aly, I’m so, so sorry,” Papyrus stuttered nervously as he took the nearest hand towel and mopped up the puddles on the surface of the table. “I shouldn’t have done that—"

“No,” Aly asserted. “I wasn’t even paying attention. It was wrong of me to yell at you like that." She felt the blood rushing to her face. Was there some sort of repercussion to snapping at the Captain of the Royal Guard? If so, she deserved it. Her lack of sleep had just left her so jumpy, so irritable.  "I'm just…” Aly trailed off as she tried to find the words to accurately describe her distractions. She had been debating on whether or not she was going to tell the brothers the details of her nightmares. However, something about sharing them felt… wrong.

“You’re severely lacking sleep,” Papyrus remarked before Aly could finish sifting through her muddied thoughts. Luckily, his voice was more concerned than it was upset with her. “Did those nightmares keep you up again last night?”

Hesitant, Aly nodded. She couldn’t lie to him.

Papyrus sighed as he unraveled his stained scarf from his neck and draped it across his forearm to dry the coffee spots. “I don’t suppose it’s something you’d want to talk about?”

Aly wanted nothing more than to talk about it. Making the effort to avoid talking about it was beginning to eat away at her just as heavily as the sleep she was losing. However, it was in the same vein that she felt like she couldn’t. The indescribable imprints of facing her own death night after night weren’t anyone else’s burden to carry. Not Papyrus’, not Sans’, not her sister’s.

The doctor was speaking to her - and only her - for a reason. She wasn’t going to jeopardize that now.

“I’m fine,” was all Aly could think to say.

Papyrus grimaced at her response disappointedly. Aly knew it wasn’t good enough, but it was the best she could do. Well, maybe she could do a  _little_  better.

Aly continued, “But… I think I could go for a walk.” She looked up at him, searching for any indication of approval on his face. “If you’re okay with having a partner today.”

“Of course!” Papyrus’ expression picked up immediately, as if the previous moments of confused anguish didn’t even happen. “I was going to walk to Waterfall today to acquire more of that nausea remedy for Mimi. To what effect it will still help at this point, I am unsure. But it’s worth a try, right?”

Aly felt a pang of guilt in her chest as her mind wandered to Mimi. The first night Papyrus and Sans had come back with that home-brewed concoction for Mimi, it did help a bit. Her stomach had settled just enough to hold back the vomiting for a few hours.

However, it came back, violent and more frequent. Her fever spiked. She faded in and out of consciousness even quicker. The wound on her leg was discharging so profusely that the bandages alone could no longer contain it for a day.

They had been out of options for a long time. But now, they were also running out of time. If Aly couldn’t find the figure from her dreams soon, she was going to lose everything.

“I can’t imagine she’s going to get any worse.” Aly’s voice cracked as she spoke. Acknowledging her sister in this condition crippled her.

"So by process of elimination, that means she can only get better." Papyrus smiled gently. Aly forced a smile in response, knowing that Papyrus was trying his hardest to keep her optimistic. But she was bending too quickly. Too many things were pulling her down, making her feel like she was moments away from shattering into a million pieces.

Aly followed Papyrus into the living room, where Sans sat on an ottoman by Mimi's side. He didn't even take his eyes off of her when the two entered.

Aly rushed to her sister and kneeled down beside the couch. Mimi looked worse each time Aly left and came back to her. All of the color was gone from her face and her bones were beginning to protrude against her skin from a substantial amount of weight loss in such a short time span. Her cheeks were hollow as she struggled to breathe.

The sight alone brought Aly to the edge of nausea. She could barely recognize her own flesh and blood; her own twin sister.

"H-How is she?" Aly stuttered. Another empty question with no good answer to come from it.

Sans gave Aly one quick glance before focusing back on to Mimi. "She woke up once and took a sip of water, so that's good news... Can't say much else."

Aly could feel her body trembling. If only this were all just a bad dream, too.

She felt a brief touch graze her shoulders followed by, "I'll wait for you outside. Take all the time you need." And before she could even respond, Papyrus had exited the house, leaving her and Sans in a dense silence beside each other.

"Leaving again?" Sans sighed.

"We're going back to Waterfall to get more of that... stuff." Aly wasn't sure what to classify the concoction as. It wasn't medicine in any regard, but it was the only thing that had helped, even in the slightest.

"You realize that's not going to do anything." Sans answered blankly. Aly knew what that tone was: Sans was detaching himself. Even as he stayed planted at Mimi's side, he had already given up on her. This infuriated Aly, but she had to pick her battles. Now was not the time to provoke useless fights with someone who probably couldn’t care less.

"Don't say that." Aly forced the words that she barely believed out of her mouth.

Sans let out a small, deflated chuckle. "Heh, you two really are the same. You never know when to call it quits."

Aly shook her head. “No, that’s all Mimi. She’s much stronger than I am. That's why... she's going to be alright." Aly turned her body towards Sans and stared at him until he finally broke his focus on Mimi again to look back at her.

They sat staring in silence as the seconds passed by slowly. There was that unspoken understanding again.

"She's... going to be alright." Sans repeated Aly's words unconvincingly.

The emptiness of Sans' words only made Aly feel worse. Frustration tightened in her chest as she pushed herself back onto her feet and stepped away from Sans, who was still staring at her. She silently slipped her boots on at the door and didn't dare look back at him before flinging the door open and slamming it shut with just a little too much force to stay inconspicuous.

When the door closed behind her, she rested her back on the smooth grain of its wooden surface. Her visible breath in the winter air became harsh and irregular as she tried to hold her building anger in.

"Aly...?" That familiar voice broke through her blinded rage. Papyrus was standing directly in front of her, hands in the pockets of his uniform and his stained scarf dried and draped around his neck once again.

Aly looked at him, but couldn't find any words to say without the fear of losing control of her emotions.

Papyrus picked up on this immediately as the silence between them deafened. "Aly, it's okay," He assured. "Did Sans say something to you? I apologize for his behavior... I suppose we've all been under an incredible amount of stress lately."

The truth was that, for once, Sans hadn't said  _enough_.

"It's nothing." Aly exhaled deeply to calm herself before she started to walk. After a moment, Papyrus followed. His long strides made it effortless to close the gap between them.

"Listen," Papyrus started. "I know Mimi is your sister, but you don't have to go through this alone."

“You’ve done too much already.” Aly clenched her fists. ”It’s always just been the two of us, I'm used to it.”

"But now you have us."

Papyrus' statement made Aly stop for a moment. However, she couldn't conjure up the right words to say. She couldn't argue with him, or tell him why that wasn't enough, or simply just thank him for his support. Aly couldn't say anything. So she continued walking.

The duo's footsteps echoed asymmetrically through the damp, dark caverns of Waterfall. Glowing blue flowers lit the pathway forward as Papyrus remained steadfast with Aly quickening her pace every so often just to keep up with him. She had never been this far east before, and would have undoubtedly gotten lost if she were by herself. However, Papyrus knew every twist and turn as if he had walked down the same paths hundreds of times before. All the while, the blue flowers illuminated the way and reflected light off of the running river that Aly had recognized from before. It was the same river that the River Person sailed on. She wondered if they would encounter them this far in.

"These are so beautiful," Aly exclaimed, running her hands across the silky petals of the glowing flowers as they walked past.

Suddenly, a delayed echo rang out directly from the last flower she had touched,  _"These are so beautiful."_

Aly jumped at the action. Papyrus looked back at her and chuckled lightly.

"These are called echo flowers," He explained. "They repeat the last thing they hear."

 _"—last thing they hear."_  Another flower mimicked Papyrus' voice.

Such peculiar things. As many notes on flora her parents had left in their journals, they had never encountered any like this on the Surface.

"I guess Waterfall isn't the place to share secrets, then," Aly joked.

"Perhaps not," Papyrus confirmed. "However, many people like to whisper wishes into the flowers. I suppose you could always try that."

Aly had no interest in wishing - that was Mimi's pastime. Her sister lived in her fantasies; wishing for a beautiful home to return to, wishing for true love, wishing mom and dad would come back. One of them had to keep them grounded to the present, where none of those things ever happened.

As they continued to walk, Papyrus plucked some of the smaller echo flowers from their stems and bustled them together in one hand. Their collective glow acted like a dim guide through the darkness. Aly couldn't help but acknowledge the contrast; an intimidatingly tall skeleton dressed in black holding such a delicate bouquet.

The single dark pathway they had been walking suddenly branched out into a series of paths and bridges leading in several directions. The cavern was now brightly lit with the bioluminescent glow of several ponds, separate from the main river. The stones on the walls gleamed brighter than ever in the light of the brilliant water phenomena. Even under the taxing circumstances, it was one of those most beautiful views Aly had ever experienced.

The awe of their surroundings must have been rich on her face. “It’s not much farther to Temmie Village,” Papyrus announced, pointing in the direction of one of the splitting pathways. “However, the rest of the path isn’t nearly as scenic as this area. You could wait here if you’d like to take a better look around. You seem quite taken with the area.”

Aly nodded, still soaking in the setting. “That… actually might be nice. Besides, Sans told me once that the Temmies are… a little hard to handle."

"That is a gross understatement," Papyrus sighed. "But they have the proclivity for obtaining the odds and ends that you need, so I choose not to question it. As long as you pay generously and don’t stop for conversation, it’s a fairly painless process.”

Aly chuckled under her breath as she scanned the immediate area, already looking for a spot to settle on once Papyrus was gone. As much as she wanted to explore, her fatigued body was begging for a moment of rest. She spotted the perfect wooden dock just a few paces away, overlooking one of the small rushing waterfalls that probably contributed to giving this place its name.

"Here." Papyrus pushed the bouquet of echo flowers against Aly's chest.

"W-What are these for?" Aly stuttered. She cradled them gently in her arms as they whispered echoes of her reluctance.

"I know you may think it's silly, but just give it a try." Papyrus was referring to his previous suggestion. "Having a little hope never hurt anyone."

So _that_ was the reason for these. As much as Aly wanted to express her extreme lack of interest in whispering sweet nothings into flowers, she held back. She constantly reminded herself that everything Papyrus ever did was an attempt to make her feel better. It was no one's fault but her own if it never did.

"You're right," Aly said. She caught herself saying that to Papyrus a lot, but he seemed to like it.

"I'll come find you afterwards." And with that short sendoff, Papyrus was on his way, never waiting on Aly's delayed responses. This never bothered her, because there were so many instances when she didn't even know what to say. Papyrus must have known this, and she was grateful that she never had to pretend with him.

 

The wood of the nearby pier creaked tiredly when Aly stepped onto its rotten planks. She tried to envision the Underground's former glory, from when it bustled with monster life. However, looking beyond the dismal landscape she had grown so accustomed to these last few weeks was hard. Imagining this place teeming with human tourists was even harder. Aly almost felt as if humankind didn't deserve to step foot in a place so beautifully unsullied.

As she reached the end of the landing, Aly carefully seated herself on the damp wood and let her legs dangle over the florescent blue water. She held the bouquet of freshly picked phosphorescent echo flowers in her hands.

 _This is stupid._  Aly plucked one from the bunch and set the rest down in her lap.

She held the single flower up to her mouth, still skeptical.

"I wish Mimi would get better," She whispered at a barely audible volume. The echo flower repeated it in the same hushed tone before she set it down and picked up another.

"I wish we could go home."

And another. "I wish we didn't have to travel ever again."

"I wish we never fell down here."

"I wish Papyrus would stop being so nice to me."

"I wish—" It took Aly a moment to realize the tears now streaming down her face as she set down the last flower before she could finish speaking into it. She hadn't allowed herself to cry during the entirety of their stay in the Underground. She didn't even want to cry now. But the tears wouldn't stop. They built rapidly from a quiet fall into a gasping sob as she withdrew her legs from the side of the dock and curled them into her chest.

She was tired of being strong.

The echo flowers, now scattered by Aly's side, had all picked up on her audible sobbing, overwriting her previous wishes with white noise as their sounds bounced off one another. Aly kept her head buried in her knees, trying her hardest to silence her tears before Papyrus returned and saw her like this.

However, Aly already knew she was too late when she felt the vibrations of silent footsteps approaching the edge of the dock. She lowered her head further, waiting for Papyrus' voice to worriedly ring through the muggy air.

She was surprised when the footsteps stopped and there was still no response.

With eyes still filled with tears, Aly tilted her head back up and was taken aback to see the figure now standing beside her was not Papyrus at all. The stranger was small in stature with dry, scaly skin under their plaid shirt. A lizard monster of sorts, which wasn't uncommon. In fact, Aly had met many reptilian monsters on the Surface. However, this one was strange. Their features from skin down to the spines on their back were the same shade of dull gray, as if the color had literally been sucked from their being. They kept their eyes forward, but Aly could tell from her vantage point that their pupils were empty, lifeless. She had never encountered anything like it.

"O-Oh, I'm so sorry," Aly faltered as she quickly wiped all of the various fluids from her face with her sleeve. "Am... Am I in your way?"

The monster continued to silently stand there, staring into the distance.

 _Okay then._  Aly scooted off to one side, hoping that would help. However, it was extremely unclear as to what the monster wanted.

Still no response.

"So..." Aly started uncomfortably. "Is this your spot or something? I'm sorry if I'm intruding, I've never been here before."

"I have no place." The gray monster finally spoke. Something about their voice was... off. The air around the words felt foggy, as if they were too transparent to fall onto most ears. The monster was speaking to Aly as well as no one in particular all at once.

"Everyone has a place." Aly tried to meet the stranger's cryptic remark with comfort. She gestured to the empty space beside her with a gentle pat onto the wooden planks, unsure if they even noticed or cared. She was pleasantly surprised when the monster lowered themselves beside her, sitting with their legs crossed tightly.

"If you haven't noticed, I don't really belong here either," Aly exclaimed after a moment in silence. "But I belong somewhere, I think. I may not know where that is yet, but it's out there."

Another long pause.

Finally, the monster spoke again, "Have you ever thought about a world where everything is exactly the same... except you don't exist?"

The question took Aly by surprise. She turned to the monster, who had still not taken their empty gaze off of some invisible point in the distance. "What does that—"

"Everything functions perfectly without you..." They continued in compete disregard of Aly's confusion. 

"I'm... not following."

The gray lizard let out a series of laughs that carried no weight to them. Robotic, empty laughs. "The thought terrifies me."

"But surely there would be someone that remembers you." Aly continued her attempt to be reassuring. She wasn't sure why she felt the need to comfort this stranger. Perhaps it was exactly the distraction she needed right now.

There was no response. So she continued, "It could be anyone. Family, friends, acquaintances... even just someone you've only met once. If it makes you feel better, I'd remember you."

Aly finally elicited a response from them. They turned their head towards her, gazing through her with soulless eyes. "And what about you, human? Who will remember you?"

"I have a sister." Aly smiled at the thought of Mimi. "We've been to Hell and back together. I don't think she could forget about me, even if she wanted to..." Suddenly, a terrible thought occurred to Aly. Her sister's time was limited. There was the very real possibility that Mimi wouldn't be around for much longer to keep Aly in her memories. She would be alone, and then she would be forgotten. Without Mimi, the entirety of her being would be reduced to nothing.

 _Oh god._  Aly's hands began to tremble at the notion. The feeling of fear came crashing back over her in waves. She couldn't lose her sister. 

The involuntarily tears were returning. In front of a stranger, no less.

The monster, although still facing her, sat silently as Aly tried to wipe away the continuous waterfall from her eyes.

"Hah... I'm sorry," Aly apologized again in between half-sobs and half-laughs. "I just can't seem to keep it together today. Maybe your fear is warranted. My sister is... and when she... I won't..."

Once more was there silence between them with only the faint noises of running water surrounding them. The monster had turned their head away again before rising to their feet and turning towards the direction to leave the dock.

"Your sister," They say in their strange, transparent voice. This time, it was lined with inflection that sounded like a combination of curiosity and reluctance. "Yes, I see now... she is the one. Doctor Gaster will take care of her."

The statement barely registered with Aly as she sniffled. "W-What—"

"...Please don't think about this anymore." The monster began to briskly walk away into the darkness of the caverns, as if they had said too much.

"W-Wait...!" Aly stumbled to her feet and tried to chase after them. Her vision was still blurry from her watery eyes as she ran off the dock and aimlessly into the dark. She yelled deeper into the cavern, "What do you know about my sis—"

Suddenly, Aly slammed her entire body into another surface with a heavy  _thud._  She staggered back, as did whatever she collided with.

"Aly!"

_Shit._

"P-Papyrus." Aly could make out his tall outline in the faint glow of the water light. He held a dirty glass flask in his hand, an indiscernible brown liquid sloshed around inside of it.

"Are you alright?!" Papyrus' voice was panicked.

"I'm fine, I just—" Aly paused, unsure of how to explain the unusual encounter that just occurred.

"Were you calling out to someone?"

"Yeah, I..." Aly wished she were better at lying on the spot. "I thought I saw someone go that way."

Luckily, Papyrus wasn't one to ask too many questions. "That's impossible. There's only one pathway out and I didn't run into any other monsters on my way back from the village."

"Heh, I must be going crazy." Aly chuckled uneasily. In reality, that was a very plausible explanation. Papyrus probably wouldn't have believed her story even if she did decide to tell him. It was just way too convenient that she would run into that monster. The idea that they seemed to know about her sister startled her. Not only that, but the very last thing they said was starting to set in as well.

_Doctor Gaster._

"I think you just need some rest," Papyrus exclaimed. As always, he was right.

"I... think so too."

"The River Person is docked just up ahead, we can take the ferry home."

Aly nodded. "That sounds perfect."

Papyrus grinned as they began to walk towards the main river again. "Did you make any wishes?"

"...I did, actually."

"And?" His face was hopeful.

"I think it did help." Aly wasn't even sure if she was lying at this point. 

"You see? You just have to stay positive! And even if you can't, I'll stay positive for the both of us!"

Aly blushed, thankful that it was now too dark for Papyrus to notice. He was too kind, just like Mimi. And she didn't deserve any of it.

 

The chaos as they arrived back in Snowdin was a blur. Something had happened, and Aly couldn't wrap her head around it.

A handful of townspeople were crowded in the living room. Bunny, and Fuku, and monsters Aly didn't recognize. They surrounded her sister in a mess of old medical books strewn across the floor, but made a path for Aly once she entered through the front door.

However, she was frozen, plastered to the ugly, dated carpet in the open doorway. Everyone was talking, but no words made sense.

"...won't wake up—"

"...heart stopped—"

"...stabilize her—" 

Sans was yelling at her, but his words were muffled by her clouded thoughts... or lack thereof. He yelled and he yelled before unapologetically shoving her out of the doorway and storming out after she didn't respond.

Papyrus grabbed both of Aly's arms and leaned down so that his eyes met hers. His features were gentle, masked behind the chips and scars that decorated his skull. But his voice was frantic as he called out to her.

Nothing.

"I... need to sleep..." Aly finally mumbled after realizing her silence would no longer suffice. She had no idea what she was doing, or what was happening, but this was the only thing that was clear to her - she needed to sleep. 

Everyone was shocked with her single, useless response as the volume of the collective voices grew louder, angrier.

Papyrus silenced them all with a raise of his hand. "My room." He understood. Always, always understood. "Take as much time as you need."

Aly dragged herself past the crowd of glaring townspeople surrounding Mimi and climbed up the stairs. She didn't look back at any of them - not even her sister. She didn't _want_ to see what kind of condition Mimi was in.

The whispers from downstairs grew louder once more as she opened the door to Papyrus' room and shut herself in. She could hear their muffled voices through the door.

"What's her problem?!"

"She doesn't even care!"

"Mimi won't make it past tomorrow."

 _Go to sleep._ Aly stumbled onto Papyrus' bed and laid atop the neatly made sheets.  _Go to sleep._

She forced her eyes shut as she exhaled slowly and counted backwards from ten in her head.

_10... 9... 8..._

_Go to sleep._

_7... 6... 5..._

_Find him._

_4... 3... 2..._

_Save her._

 

Aly wasted no time once she discovered she had successfully made it back into the void.

"Doctor," She called out through the empty abyss.

"There's no more time. You know what I need," Aly continued to announce desperately as her voice echoed infinitely.

The familiar shudder of the darkness coming to life began to reverberate around her. She shifted her stance, readying herself for any impact. 

"Tell me where to find you."

The quake of the void boomed. Aly remained unwavering.

"Tell me how to reach you, _Doctor Gaster._ "

Suddenly, all movement came to a staggering halt when that name rang through the thin air. After a still moment of unsettling silence, the distant hum of white noise began to envelop the area. Aly was used to this now; her head had adjusted to the noise and no longer throbbed when it returned night after night.

However, there was something else this time. Underneath the static was a low, rumbling gurgle that sounded like a thick, viscous wave approaching her. Closer and closer, Aly could feel the movement cutting through the darkness. 

And then it was in front of her. She couldn't see it, but she felt its presence. She extended her hand out in the approximation of where she felt the wave manifesting. In immediate response, a boney hand emerged from the darkness and latched onto her wrist. Its crackling fingers wrapped itself tightly around the entirety of her hand and jerked Aly so hard that she nearly lost her balance.

She was aghast by the sight of the hand, seemingly disjointed from any sort of body. It appeared to be akin to a human skeleton hand, but much larger with a gaping hole through the palm. She tried to pull away, but the hand did not budge from its point in space. 

"N-Not very welcoming, are you?" Aly grunted as its grip grew tighter against her resistance.

All of a sudden, another floating hand emerged from the darkness. Without missing a beat, it began to sign several symbols in the same manner that the doctor had attempted to communicate with Aly before.

The craziest revelation was that Aly could understand it this time.

"R-O-O-M—" She spelled out aloud as the hand shifted from one sign to the next. "2-6-9."

The white noise roared in what Aly hoped was approval and the hand clutching onto hers so firmly had released her.

There was another uneasy stillness when suddenly, another figure emerged from the abyss. It was a skull, resting atop the tangible mass of oozing darkness. Its features were melting, leaving Aly barely able to make out anything but an unnerving grin. The hairs on the back of her neck stood on end at the sight. Only in her deepest nightmares could something this grotesque come to life. Was this _really_ Doctor Gaster...?

Aly could feel the inky black liquid pooling at her feet and rising rapidly to her ankles, then her knees. Before long, it was up to her waist, and its substantial density made it impossible to wade though. She was stuck, drowning, as the doctor himself stood in front of her and watched.

 _Stop stop stop._ Aly wheezed as the liquid reached her neck and continued to rise too quickly for her to think of a way out.

Even though she knew it was a useless gesture, Aly held her breath before the darkness completely swallowed her, stealing one last glance at that melting skull and its floating hands signing the same characters over and over again.

_Room 269._

_Room 269._

And then it all reverted back to nothing.

 

...But that wasn't the end.

When Aly opened her eyes, she was back in Waterfall, curled right in front of the same dock she had chosen to rest on earlier. The water, while still emitting that strange florescent light, was now black. The beautiful echo flowers that lined the ground were now covered in a thick layer of melting, black sludge. Some of the bridges and pathways led straight into walls, as if they had been incorrectly placed in her fragmented memories of the area. None of it made sense.

She saw a figure at the end of the pier, sitting right where she remembered inviting them.

"You." Aly approached the familiar monster, dressed in the same plaid shirt and dead gray wash.

"I told you to forget about this... To forget about me." They didn't turn to face her.

"And I told you that I'm not going to."

The monster went silent before letting out another one of those empty, expressionless laughs. "Ha, ha... You know, that does make me feel a little better about this. Thank you."

"...Why am I here again?" Aly asked. This dream was so jarringly different than all of the previous ones. It was progress towards her goal, but still puzzled her nonetheless.

"You're going to find the doctor."

Aly was still confused. "H-Here...? Room 269 is in Waterfall?"

The gray monster finally stood up, still with their back to Aly.

"You'll find him."

"But I don't know—"

"You're going to wake up now," They exclaimed mechanically. "...And you're going to forget about me."

"N-No! Wait wait wait. Just, please... I—"

"Stay determined, Aly."

Without warning, the distorted world around Aly began to crumble apart. Within seconds, everything fell into darkness until there was truly nothing left.


	8. The Hidden Door in Waterfall

**Summary for the Chapter:**

> Aly goes to search for Room 269, but not before finally giving Sans a piece of her mind.

**Notes for the Chapter:**

> The Sans/Aly hate ship has sailed and it's kind of our favorite thing ever.
> 
> Short chapter this week as we prepare for what comes next. The next few chapters were actually the very first ideas we fleshed out for Undertaken and what inspired us to create a full fanfic. So while they're technically already written, we plan to spend some extra time with scene rewrites and edits. Updates might have to be spaced out a bit more, depending on our schedules. Every other week, maybe? But certainly no longer than that! Regardless, we'll still try our hardest to get them out every week when possible. In the meantime, we have been trying to update our [Tumblr](http://anundertaleoftwosisters.tumblr.com/) with more art/sketches in between chapters.
> 
> As always, thanks for the support and for sticking around this long. Now things get... _very, very interesting._

All Aly could feel was the sensation of falling. Falling endlessly into nothing.

It was... freeing. For the first time in ages, she felt like she had nothing to worry about. Nothing at all mattered. She couldn’t even remember why she was falling anymore. And the longer she fell, the more those distant, painful blurs of memories from earlier in her dream melted away.

But suddenly, there was a precipitous moment of clarity. And in that moment when Aly remembered what she had to do, the ground appeared beneath her. It was a familiar setting; a clearing painted gold in a sea of buttercups, reminiscent of their descent into the Underground. Aly closed her eyes and continued to let herself fall, tensing up slightly as she anticipated impact.

_Stay determined, Aly._ The voice in her head wasn’t her own, but she couldn’t place its familiarity. Nevertheless, it was comforting. She was ready.

_Stay determined._

Aly's body shot up from the bed just before she hit the ground. She clutched her chest tightly, a throbbing pain coursing through her entire torso as her heart beat at maximum capacity. Cold sweat mixed with tears poured down her face as she tried to catch her breath. The sky outside of Papyrus' bedroom window was still black. It wasn't quite morning yet, but Aly was unsure of the exact time. However, it didn't matter.

_The dream,_ Aly reminded herself as she scrambled to her feet, shoes still on from when she was chasing sleep too desperately to take them off. Strangely, pieces of this dream were hazy now. All she could remember before falling were brief glimpses of fleeting locations in Waterfall... and a room number. A room number given to her by Doctor Gaster.

_Room 269._

That was important, but Aly could barely remember if there was anymore to it. Hopefully everything she had retained would be enough.

The door squeaked open as Aly peered her head out into the hall and down beyond the second story railing. It was dark, with only a dim light emitting from a table lamp at the far end of the living room. In its light, she could see her sister’s vague silhouette, lifeless on the couch. If she was breathing, it was too shallow for Aly to see from this distance.

Beside Mimi rested that familiar small-statured skeleton, slumped in a chair with the hood of his jacket flipped up to cover his face. Aly couldn’t tell if Sans was sleeping… not that she cared. She was leaving regardless of whether he saw or not.

The stairs creaked under Aly’s steps as she entered the living room. Sans didn’t budge. It wasn't until she began to unlock the front door that he finally stirred.

“Well, someone's up early.” His voice was gruff as if he'd just woken up, but Aly remained unconvinced.

_Dammit, Sans._

“I have to go," She retorted crassly.

"Right, shouldn't have expected any less." Sans yawned as he pulled his hood off. “And what’s the hurry this time?”

“Saving Mimi’s life.”

“Heh, very  _humerus_ of you. Don’t know if you’ve noticed but..." Sans leaned over and extended a finger towards Mimi, lying so peacefully despite everything she had been through. "You already failed once.”

And just like that, a switch was flipped in Aly's head.

“…What did you say?”

“Why not just relax today? You haven’t been getting much sleep. Well, you know, with the of exception last night." Sans shrugged nonchalantly as he inclined further in the chair, now balancing on its two back legs. "Man, you sure pissed a lot of monsters off with that act of yours. I don't think there's a single monster in Snowdin that still likes ya after your complete disregard for the well-being of their favorite human."

Aly was shaking in bridled anger. “Sans, stop it.” He just didn't get it. He didn't know how it felt. He didn't know the lengths she was going to for Mimi.

But Sans didn't stop with her request. He malevolently pressed further, “So, where are you off to this time? Paps is still asleep in my room, if you were hoping to cavort on his patrol again.” Aly couldn't tell if Sans was angry or if this was all just a game to him now. “Which, heh, by the way, I’m not okay with. Big bro’s gotta step in at some point.”

“…Don’t patronize me." Aly couldn't keep her hand from trembling against the metal of the door handle as she swung the front door open. "You don’t understand anything.”

The winter wind pricked at her skin as she faced the early morning darkness. It was a reprieve from how hot her blood boiled.

“Aw, come on, don’t give me the _cold shoulder_ now.”

_Unbelievable._ Aly was abhorred by Sans' words. He was pushing her on purpose. 

Just as she reached to slam the door shut behind her, a sudden force jerked it back. When she turned her head, there was Sans - emerging from seemingly nowhere as he often did.

"I said stop ignoring me,  _sweetheart."_

"What the fuck, Sans!" Aly was more startled than anything. Well, that wasn't true; she was furious. She always meant to question his innate ability of showing up exactly where he wasn't wanted, but it had come to the point where she just didn't care. She just wanted it to stop.

The lights in Sans' eyes were dark now as he forced the door open against Aly's pull. “Whatever you're going out to look for, I guarantee you're not going to find it. And it's certainly not more important than the kid's life."

"You don't  _get_  to act like you care about her now," Aly spat angrily as she seceded the door to him and stormed out. The heaviness of her irate steps sunk through the crunching snow. At this point, she wanted nothing more than for this conversation to be over.

But of course, Sans wasn't going to make it that easy. Even as Aly continued to walk farther away from the house, she could feel his persistent presence behind her. 

"So what do you call everything I've done for her, huh?" Sans' mirthless tone was finally matching Aly's hostility. "Keeping her happy, cleaning her wound, staying by her side every waking minute that YOU weren't there."

Aly let out a sharp crow in riled amusement. "Don't lie to yourself. You gave up on Mimi a long time ago."

"But have you noticed yourself recently? You haven't been here, mentally or physically. Retreating into your head is just as bad as giving up. So if I'm terrible, then so are you, sweetheart."

The volume of the argument grew, echoing through the thin air. " _She is my sister,"_ Aly growled. "Do not compare me to YOU."

Sans wrenched Aly's arm back and pulled her forcefully to a stop. He was shaking now too, his own voice carrying loudly without any regard for who heard at this point. "You. Weren't. Here. Her heart _stopped_. And you weren't here!" His grip tightened around Aly as he dragged his other hand down his face. "I mean for godsake, the fucking  _townspeople_  saved her. She was dead, and they brought her back. People don't just get second chances like tha--"

Sans' shouting stopped abruptly, as if removing himself temporarily from the exchange and into his own thoughts.

However, Aly wasn't finished yet. Oh no, she was far from finished with him. She jerked her arm back from Sans and shoved him away with a firm jab to his sternum.

"I've seen the way you look at her with so much remorse. Like she's already dead." Aly pushed him again. He staggered slightly this time, almost just allowing it to happen.

"You've been too busy detaching yourself to even notice how much she cares for you. How hard she's fallen for you. Because that's what Mimi does; she falls fast, and she falls hard." Aly took another step towards him, drawing him even further back.

"And it  _repulses_  me to see you treating her this way in return. Putting on the front that you give a shit as you let her die."

Aly was towering over him now, rattling hands clutched at the collar of his jacket. "She's far too kind for you. Too caring, too loving. You don't deserve her kindness. You don't deserve any part of her, even when she's given you everything."

At last, Aly had wiped that smug grin off of his face completely.

Her words hung heavily in the air as she let go of the skeleton.  "I'll never stop fighting for her, Sans." 

Sans rubbed his chest, as if Aly's advances actually caused him a bit of physical pain. "Look, you may not believe this, but... I care about your sister more than I thought I was ever capable of caring for another human being again. But you're making a mistake. She might be gone by the time you get back from... god knows where."

Aly grimaced at the thought, but she had no choice. This was the only option she had left. “If this were Papyrus, don't tell me you wouldn't do everything you could to try and save him. Even if it seemed crazy, or dangerous, or even completely impossible."

The mention of his own brother made Sans waver. "...Of course I would."

"Then let me save her." Aly was finished talking. She turned on her heels and broke into a sprint without even waiting for a response.

Sans didn't try to stop her again.

 

Aly played her fragmented dream back in her head over and over as she stepped off of the River Person's boat and onto the dock in Waterfall. Specifically, she tried to envision what little she could remember of Doctor Gaster and his strange sign language that she still had a slight grip on.

"Thank you." Aly bowed politely at the cloaked figure perched at the front of the wooden boat, whom she was quite comfortable with now. She had found many reasons to use the ferry services lately.

"I will be here when Miss Aly wishes to return home," The River Person announced in their sing-song voice.

The vaguely familiar caves beyond the river were just as dark as she remembered. It had been less than a day, but she was still relatively new to these specific caverns, now more daunting without Papyrus there as a confident guide.

Aly tried her best to keep a mental note of every weaving pathway and bridge she came across. Echo flowers and glowing mushroom caps lined the ground beneath her, but she was careful to not step on them. She also remained as silent as she could, as to not be picked up by the ever-listening flora.

After walking deeper in, the feeling of déjà vu began to overwhelm her, even if she had never stepped foot in many of these areas before. A yanking feeling in her gut indicated that she was getting close. From that point, Aly let her heart take the reins – finding the right path solely on instinct and occasionally "recognizing" landmarks that confirmed to her that she was going in the right direction. Her greatest fear at this point was that none of this even mattered - that she was so far off from the mark. But, as hard as she tried, she couldn't remember a single concrete detail about where this room was. Intuition was all she had.

 

After that, finding the door was almost  _too_  easy. Upon reaching Waterfall, it only took maybe another hour or so for her to finally discover a hidden corridor behind one of the cavern walls.

And there it was, plain as day.

A bit underwhelming, the door was small with a monochromatic gray finish. At first, Aly even questioned if it was the correct door. Though the presence of a door at this location in the first place was already unheard of – of _course_ it was the right door. It had no embellishments except for its knob and three small images etched into the center. The first was a piece of paper, the second was an hour glass, and the third was a tape measurer. It didn’t occur to Aly immediately that she was still able to subconsciously translate those images into numbers. However, once she did, everything fit together like an unfinished puzzle.

Room 269. Exactly like  _he_  instructed. Granted, the instructions were as unhelpful as they could have been, but that wasn't important now.

Aly felt a wave of anxiety wash over her as she grabbed the door knob and found that it was unlocked, as if her presence was already expected. This was all happening so fast, and yet not fast enough. She inhaled a deep breath to calm herself before opening the door, using every ounce of her energy to will her legs to walk inside and shutting the door closed behind her.

Inside the door awaited nothing but mind-numbing darkness. It was too familiar, _too real_. Panic began to set in as Aly tried to reach for the door again, only to realize that she could no longer find it. In fact, there was nothing behind her anymore. No walls, no door.

Just the looming feeling of someone watching her.

Aly could barely keep her whole body from trembling as she stood at the center of maddening darkness. Somehow, she conjured up the willpower to speak.

“Doctor,” She called out into the vast nothingness. Her voice carried, but not very far. There had to be a finite amount of space in this room, even if she couldn’t see it.

“Doctor Gaster.”

Suddenly, for the first time outside of her dreams, she heard it. The unsettling, broken voice that almost didn’t sound like it could possibly exist within this plane of reality. Aly still couldn’t see anything, but she felt _his_ presence right behind her.

The ringing in her ears returned as the voice hissed sounds into a disjointed phrase that Aly could actually make out without any sort of translation.

**"I've been waiting for you."**


	9. The Doctor

**Summary for the Chapter:**

> Aly's encounter with W.D. Gaster is not quite what she expected. It seems that everything is going to be alright for now.

**Notes for the Chapter:**

> We were determined to get this chapter out this week. Sorry it's a bit short! But here it is, along with the goop man himself being... very generous.
> 
> Originally posted on [Tumblr](http://anundertaleoftwosisters.tumblr.com/).

Aly couldn’t bring herself to turn around. She could find the courage to seek out the doctor, and to even speak to him…

But not to face him.

Her fear must have been nearly tangible as the darkness itself began to feel thicker. Aly felt herself suffocating as if it were forming in thick toxic clouds around her; a culmination of all of her nightmares manifesting into reality.

In that exact moment, she felt a large, bony hand wrap itself around the entirety of her shoulder. The gaping hole where a palm should have been was an image too ingrained in her head to mistake it for anyone else's hand. It dug into her skin so callously that she was forced to turn around just to pull away from it.

Aly wasn’t sure what she was expecting to see. Gaster had presented himself within her dreams in such obscure forms. In front of her was a figure somewhere in between corporeal and one with the darkness itself. His stark white skull contrasted against the black robes draped loosely over his shoulders that seemed to disappear into the abysmal shadows surrounding him. The right side of his head looked as if it had been split open all the way down to his drooping eye socket. The left eye was in better shape, with only a few thick hairline cracks underneath it. His mouth was thin and barely visible, unlike the real, toothy anatomy of a skull. Sans and Papyrus always wore large grins that were surprisingly warm and inviting, despite being skeletons. Gaster’s grin was… unnerving. Just as unnerving as the broken words that spilled from it.

“I’m so pleased that you found me.” As Gaster spoke distorted strings of barely audible sounds, his skeletal hands signed different symbols in the air. They moved so swiftly and fluidly, it was as if they weren’t even connected to his body. Aly could barely keep up. Seeing these symbols with her own eyes was much different than being able to understand and translate them in her dreams. Gaster seemed to be aware of this and slowed his pace.

“Do you know who I am?” He tried again. Each hand conveyed a different symbol, spelling words into a phrase two letters at a time.

Slowly, Aly was starting to recognize the patterns and catch on to the strange language. The characters themselves weren't depicted quite as literally as in her dreams, but she was able to fill in most of the blanks. Her greatest distraction came from the sheer anxiety of just being in this position - face to face with the culprit behind her sleepless nights.

“I don’t,” Aly admitted. 

She focused intently as he signed an introduction with his two hovering hands. One hand extended an index finger and thumb into a cross. The other pointed a thumb down. It revolved through characters like this. A finger pointed up. Then two fingers up on the opposite hand…

“W.D. Gaster,” Aly finished before the hands finished cycling through the name completely. “So it _is_ you. The one everyone talks about.”

“You seem less than surprised,” Gaster mused, remnants of a chuckle hung in the air around his mouth. 

“A part of me feels like I’ve known you for a long time.” Truth be told, the tingling feeling of deja vu didn’t cease upon finding the hidden door. It still crept along Aly’s bones as she faced the curious figure of W.D. Gaster. It was a sensation that stemmed far beyond her dreams and into an area that she couldn’t quite place. And as apprehensive as she was from standing in the middle of nothing but stifling darkness, Gaster’s presence itself had a certain comforting familiarity to it that she simply couldn’t understand.

“Well, I suppose that’s one reason why I’ve been trying to contact you.”

At this point, Aly had more questions than she knew how to comprehend. Once again, the confusion must have been written all over her face as Gaster’s expression lowered empathetically. Instead of trying to answer them, he moved past Aly and beckoned for her to follow with an outstretched finger on one of his hands. She hesitated at first, but eventually followed a few steps behind him and further into the darkness.

Aly was right in her assumption that the physical space they were in wasn’t very large. It seemed to have only taken a few steps to reach a wall. Against that wall was the silhouette of a table or desk, but it was too dark to see the contents of everything scattered atop of it. The rest of the room was also too engulfed in shadows for Aly to see anything else, regardless of how much her eyes adjusted. 

With his back turned to Aly, Gaster began to pick up varying components from the table, glass clinking together and papers shuffling quietly. As if the dark weren’t blinding enough, Aly would have never been able to see anything over his body that towered far above hers.

Aly jumped when two more floating skeletal hands appeared behind him, wrapped in the soft glow of magic. She hadn’t seen any monsters in the Underground use their magical abilities up until this point, but she was very aware that they were all capable of it. The floating hands signed for him as he spoke without facing her. It was apparent now that _the man who speaks in hands_ was a suitable title.

“And you’re here because of your sister,” Gaster recalled.

Aly raised her brow in skeptical surprise. “So you know.”

“I know quite a few things, darling.” He craned his head to the side as a thin smirk crossed his face briefly in mild dissipation.

Aly tried to shake the violating feeling of Gaster’s illusive omnipresence. However, seeing as he somehow had the ability to communicate with her through her own dreams, it shouldn't have come as a surprise. “Then you know that we’re out of time.”

“I know Mimi has already died once,” Gaster said frankly. “However, she will not be so fortunate to come back a second time.”

Aly grimaced. “Seems like everyone around here likes to remind me of that.” The weight of the guilt she carried from not being there for her sister was almost unbearable. But for Mimi’s sake, she refused to let it crush her. No matter what Sans, or the people of Snowdin, or even Gaster himself thought about her, Aly knew she was making the right choices. “That’s why… I was hoping you could help. Everyone calls you a doctor.”

Another amused laugh cut through the darkness.

“I’m afraid they are all sorely mistaken,” Gaster’s hands replied in unison with the continuous spill of broken, yet discernible, words. “I am merely a scientist.”

Aly felt a drop in her stomach. _Not... a doctor?_

“Then why am I here…?” Her voice cracked as she tried to assess the point of coming this far. "What has all of this led up to?"

“Because I still want to help you, Aly.” Gaster finally turned to face her again. In one of his hands separate from the ones translating his words was a capped syringe filled with a bright green, almost florescent, liquid. “Your sister is going to be fine, if that is your main concern.”

Aly kept her eyes fixed on the liquid. “...What is that?” 

"The cure." Gaster shifted a few paces forward and extended the syringe out to Aly. "It's makeup is not important right now."

Aly hesitantly lifted her hand to receive it. "But... you're sure it'll make Mimi better?"

"I guarantee it."

With that confirmation, Aly quickly grabbed it from his hand and pulled it closer to her chest. “Thank you,” was all she could manage to say at first, still in disbelief that the antidote was right there in her hands. Something about it felt _too_ easy, even if it took this long and Mimi's heart stopping once to obtain it.

“I guess I’m still a little confused, though.” Aly, while grateful, couldn’t ignore the obvious question. “Why… do you care so much? You don’t even know us.”

Gaster’s hands dropped for a moment, as if in contemplation of how to put his next response into words. The expression on his face remained unfazed, his thin grin at a rest. “We’ve never met before, but I certainly know you. Your sister Mimi as well.”

Aly felt goosebumps running up her skin. “T-That can’t be right. We’ve never been to the Underground before.”

“Not you.” Gaster was reaching for another object from the desk again. He eventually came back with what looked like a small sheet of paper, extending that to Aly as well.

“Your parents.”

Aly felt her heart skip a beat as her trembling hands took the paper from in between Gaster’s osseous fingers. It was a photograph. Her eyes adjusted to the darkness just enough to make out the outlines of two small figures in the center of the image, standing side by side.

_This isn't possible._

It was a picture of her and her sister when they were younger. Aly remembered the day that photo was taken. She could remember her father behind the camera, and the way she refused to smile for this particular photo. However, many pieces of her memories were still missing. There were always holes in the past where there shouldn’t have been. For a long time, she thought there was something physically wrong with her until she realized that Mimi couldn’t remember many of the same things either. 

“Where… Where did you get this?” Aly managed to gasp out in between her utter speechlessness.

“I’ve met them. Worked with them, even.” Gaster leaned down and smiled at Aly. His grin, devoid of any warmth, did not give her the least bit of comfort. If anything, it just made her more anxious. “Very wonderful scientists that were absolutely smitten with their twin daughters.” He inched towards her and dragged a finger over the figure of Aly’s younger self in the photo. 

_Scientists._ Their parents were scientists… just like Gaster. It was like the first layer of a dense fog in Aly’s head had dispersed. She _knew_ that. It explained all of the notes they had left behind. Why couldn’t she remember it before?  

“T-They…” Aly focused hard on the photograph to pull back even more memories. She strained her eyes to examine as many little details as she could. The lace on the matching dresses she and Mimi wore. The well-kept grass of their backyard, thick with patches of invasive golden buttercups. The little freckles that Mimi once had speckled across her skin - possibly the only way they could have been told apart as children. It was all starting to make Aly’s head throb, but she continued to mentally sift through what little fragments of her past she had.

“…They left,” she continued. “The year the barrier between the Surface and Underground was shattered. They came here… to help. To study monsters and acclimate them to living above ground.” Her eyes met Gaster’s as she looked for affirmation from him that she was remembering this correctly. She tried to recall the day her father sat her and Mimi down as he explained this to them; the way Mimi’s cries rang through the house as she begged them not to go. Sadly, Aly was still unable to remember his face.

To her delight, Gaster nodded. “They were some of the first human scientists this world had ever seen. The King and his Royal Scientist adored them and their willingness to help monsterkind.”

It eased Aly’s mind to not only remember the vague existence of her mother and father, but to know that they were kind to this world’s citizens in a way that had taken the rest of the Surface years to finally give in to.

It didn't take long for the excitement to be replaced with dread. “What happened to them?” Aly’s expression fell, but she knew she had to ask that question eventually. After all, if Gaster was in possession of this photo, it meant that they couldn’t still be around.

Gaster appeared as if he were about to give her an answer, but then his expression wavered slightly before he composed himself once again. “I’m afraid… we’re out of time for now, my dear,” he replied coldly as he redirected her attention back to the syringe in her hands. “If you don’t hurry back to your sister now, I’m afraid it’s going to be too late.”

As much as Aly’s heart ached for more information, she knew that Gaster was right. This was all for Mimi's sake - it wasn’t time to get distracted now. Stuffing the syringe and the photograph in her pocket, Aly had already made the resolve in her head to return to this place as soon as possible.

“Injecting that directly into your sister’s wound will stop the infection immediately,” Gaster explained. “It should only take a few moments for it to reach the rest of her body through her bloodstream and nullify the septic shock.” 

Every part of this encounter seemed like an unlikely dream. Aly’s mind refused to wrap around the notion that, all at once, this strange monster had all of the answers to every pressing matter she currently faced. But what more was there to do at this point than trust him?

“Thank you, Doctor Gaster.” Aly couldn’t find the words to express her gratitude. “This has all been a little overwhelming… but you’ve been very kind.” 

The doctor bowed his head courteously towards her. “You flatter me. However, I do have one request to ask of you in exchange.”

Aly nodded, it was only fair. “Anything.”

“Come back here in two days,” Gaster instructed. “I require a human’s assistance on an experiment I’ve been researching for a very long time.”

Aly’s muscles tightened with unease, but she agreed. “And if… _when_ I come back, you’ll tell me everything you know about our parents.”

Gaster smirked, entertained. “You have my word." A pause. "One more thing, darling."

"Y-Yes?"

"It would be best if you didn't tell anyone else about our meeting."

Before Aly could even formulate her next sentence, Gaster was gone and the door to Waterfall had reappeared in his place.

 

Aly ran as fast as her legs would take her back to the ferry. However, by the time she had returned to Snowdin, night was already falling on the town. What had felt like only a few moments with Gaster appeared to be almost an entire day. Perhaps she really _was_ losing her mind.

Aly burst through the door of Sans and Papyrus’ home and ran straight through the living room, tracking snow from her boots with each step. She saw both of the skeleton brothers towering over Mimi’s body, frozen stiffly in place by Aly's arrival.

“Aly! You’re back!” Papyrus called out with a relieved expression settling on his face. However, it was a short-lived relief as he looked back at Mimi. Aly didn't think Mimi could look any worse than before, but she was proven wrong. The brothers had been scrambling to keep cold rags on her head while simultaneously wrapping her in blankets. The pile of books on human anatomy that covered the floors the day before were now all opened to various pages on the coffee table. It was evident that Sans and Papyrus were desperately trying to keep Mimi breathing in Aly's absence, despite knowing very little about how a human even worked. She did feel incredibly guilty for being gone for so long. However, she was hoping this medicine was worth it. 

“Where the hell have you been?!” Sans had no qualms with raising his voice to her in his panic. Aly was sure it was especially easy for him to conjure up that nerve after their altercation earlier that morning.

“Out of my way.” Aly pushed Sans away from the couch, Papyrus naturally sliding out of the way as well. She tore all of the blankets off of her unconscious sister’s body and unwrapped her injured leg from its bandages. The entire area of skin was a dark, sickening purple that twisted Aly’s stomach into knots. But she had to hold it together.

When she pulled out the syringe from her pocket and uncapped it, she felt a hand firmly grab her arm before she could inject it.

“What is that?” Sans tightened his grip as he glared at her hostilely, then back at the green liquid-filled tube.

“Medicine.” Aly drew her arm back from him and continued to line it up with the exposed wound.

“There _is_ no medicine down here.”

“Well I guess you’ve never looked hard enough, have you?”

“Stop.” Papyrus intervened between the two of them. “You’re both acting unnecessarily childish.”

Not wanting to agree that he was right, Aly and Sans spent the next few moments in complete silence. Aly injected the entirety of the liquid directly into the wound as she was instructed to do while Papyrus helped clean it up immediately after the syringe was emptied. Sans looked on uselessly as if he could barely stand the sight of Mimi this way.

The three of them stood rigidly for a few uneasy moments as they watched Mimi's shallow breathing return to normal with one large exhale leaving her unconscious body. Her face softened after being constricted into a painful grimace for so long.

"Just like that...?" Aly whispered in astonishment as she brushed the loose hairs from Mimi's face. Even the temperature of her skin had already cooled greatly. Like magic, Mimi's body was healing itself. However, Aly was still apprehensive. What was the catch? How long would it take for something to go wrong again?

"I-It's like some sort of healing magic... condensed into a liquid form?" Papyrus scratched his chin, perplexed. "Where in the world would you find something like this--"

"Not important right now, bro,” Sans interrupted unexpectedly. “Let's move her to my room. She needs to lie in a real bed."

“Thank you, Sans.” Aly sighed an alleviated breath that Mimi was able to hold on just long enough for her to make it back. And although she felt like she was right on the cusp of finding more answers about her past, Gaster was right to cut the conversation short when he did.Granted, she had a feeling it was for his benefit to hold more leverage over and ensure that she returned as promised, but it had worked out for the both of them. She’d consider it a victory in her favor for now.

There was also no telling yet if the medicine would be completely successful, but at least Aly could say that she tried. That alone was enough to give her the tiniest feeling of ease for the time being. She was putting all of her faith in Gaster's guarantee that this one antidote was going to fix everything. So far, it looked like he was telling the truth.

“Right. I’ve got her,” Papyrus exclaimed as he was already in the middle of gently scooping Mimi’s limp body off the couch. Her breathing was completely stabilized now. “I’ll stay with her tonight if you two want to get some rest. It’s been a long day.” Before either Aly or Sans could answer, he was already carrying her up the stairs to Sans’ bedroom.

Once the couch was free again, both Sans and Aly fell into the cushions of it in tired reprieve. The tension between them was still thick enough to slice with a knife.

“You’re an idiot… you know that?” Sans finally grumbled under his breath.

“I know.” Aly was so tired of fighting with him. At this point, she didn’t have the energy to do anything at all. “I’m… I’m sorry.” 

Sans was taken aback by the apology. “This better have been worth it, sweetheart. She was cutting it real close.”

“I hope so too.” Aly's silent anxiety returned as she finally assessed everything that happened today. She made a deal with the mysterious W.D. Gaster, yet was too rattled at the time to fully grasp what she had even promised. She had no idea what these next few days would entail. But at this point, she had no choice but to find out. _Two days._

“You don’t have to tell me where you got that medicine,” Sans answered as if he already anticipated Aly trying to come up with an excuse if he had asked. “In fact, I don't think I even _want_ to know. Just don’t say I didn’t warn ya.”

“If I listened to your warning before, Mimi would be dead right now.” Aly mumbled as she rested her head on the arm of the couch and curled her legs to her chest. She was exhausted.

“Kid's not out of the woods yet.” Sans got up from the couch to give Aly more space to stretch out. He picked up one of the blankets scattered across the floor and draped it over her. Aly was incredibly surprised by the gesture.

“But,” he continued talking as he picked up the rest of the mess they had made in the living room. “I think she’s going to be okay now. Really… we should be thanking _you._ ”

“No, you shouldn’t.” Aly’s voice began to trail off as she felt her eyes getting heavier and a much-needed slumber quickly approaching. For the first time in a while, she didn't fear falling sleep.

“I’m her sister, not a hero.”


	10. The Second Day

**Summary for the Chapter:**

> Mimi is finally awake. Sans is the only one there to welcome her back.

**Notes for the Chapter:**

> We are officially halfway done with this self-indulgent shit show! To celebrate, take a hefty dose of more Sans/Mimi fluff. The last 9 (...or maybe more?) chapters are going to be longer and therefore much more spaced out, so thanks for sticking with it.
> 
> Originally posted on [Tumblr](http://anundertaleoftwosisters.tumblr.com/).

Morning was dawning on the second day since Aly had administered the medicine into Mimi's wound. Mimi’s fever disappeared immediately and the gash itself was reduced to almost nothing by the following morning. As Gaster had guaranteed, her sister came out of that nightmarish few days alive. However, she still hadn't woken up. 

Aly slowly blinked her eyes open as the light from the bedroom window to her left spilled in. She had fallen asleep hunched over in a chair by Mimi's bedside; crease marks from lying on her arms were imprinted on her face. Aly glanced over to see her sister still in the same position they had left her in Sans' bed.

Aly’s back popped and cracked as she straightened up in the seat. Today was the day she would return to Gaster and hold up her end of the deal. And the sooner she met with him, the sooner she could be back for when Mimi finally opened her eyes again. Aly grazed a wandering hand over Mimi's and squeezed it tightly in her palm. 

"Never break promises, right?" she mumbled uneasily through her audible anxiety.

Just as Aly was about to stand up, there was a knock at the bedroom door, opening a moment later without waiting for a reply. Sans stood in the doorway as the door swung open, wearing the same t-shirt and gym shorts he had been in for the last two days. Both he and Aly hadn't left the house at all within that time and barely slept. They watched over Mimi in continuous, worried shifts.

"How's the kid doing?" Sans asked groggily before Aly could even acknowledge him.

"Much better," Aly replied. "I think she's going to wake up soon."

Relief spread across Sans' face. "Good to hear. I'm sure you'll want to be around for that. So I was actually going to get out of the house for a bit and join Paps on his patrol today if you wanted to stay—“

Guilt tightened in Aly's chest as she held a hesitant hand up to stop him. "Actually... I have a favor to ask."

Sans furrowed his brow line, already anticipating what was coming. "No,” his voice was stern. “No no no. You can't keep doing this to her. If she wakes up and you're not here, she'll probably worry herself sick again… literally.”

"I... don't have a choice." Aly grimaced as her eyes fell back onto her sister. "Please, Sans,” she pleaded with a sincerity that was difficult for her to normally gather towards him. “Please stay with her. And if she wakes up, tell her I'll be back as soon as I can."

Sans sighed, dejected. For the last two days, both of them seemed to be low on the vigor to fight with one another. "Of course I'll look after her. But I'm telling ya - wherever you're going and whatever you're doing instead of being here with your sister… it's not worth it." He paused. "Take it from me. I’ve paid that price dozens of times. When you have nothing else in this world but each other, the best thing you can possibly do is _be there_.”

Aly wanted desperately to agree with him. But if Gaster was capable of communicating with her through her own dreams, then there was no telling what he could do if she didn't uphold her end of their deal. Considering his actions before, she wanted to believe that he was kinder than that. However, something held her back from trusting him completely. Perhaps it was because her dreams of him were not as pleasant. Perhaps it was just that unnerving smile of his.

Perhaps it was because this wasn’t the first time Sans had warned her. Did he know about Gaster too? Aly didn't want to push her luck by bringing it up. Not yet, at least. This was something she had to do on her own.

As Aly turned to leave without a decent response and Sans entered the room further to take her place, he mumbled something that caused her to halt in the doorway.

"Determination."

"W-What?"

Neither one of them faced the other. “Does that word mean anything to you?”

“I don’t think so.”

A pensive silence fell over them in between Sans' thoughts and his next response. “…Heh. My mistake, then. See you later, sweetheart.”

Aly continued out from the doorway and down the stairs, but stopped at the bottom. All of Sans' words were still ringing in her ears. He was right. He was right about everything. But she didn’t have the luxury of accepting that. ...And then there was whatever  _determination_ meant.

But there was no time to worry about any of it now.

"I'm sorry, Mimi," Aly breathed through her teeth as she stepped into her boots, slipped through the front door and started in the direction of Waterfall on foot.

***

The darkness was dispersing. The fog was clearing.

 _“Wake up, Mimi.”_ A familiar voice was pulling its way to the front of Mimi’s mind.

 _Five more minutes, sis._ Mimi fought back tiredly.

_“Don’t you think you’ve been asleep long enough?”_

_You always say that._

_“It’s true this time. Now open your eyes, sleepyhead.”_

Mimi stirred restlessly, not wanting to be awoken just yet from her slumber. However, the more she squirmed around, the more she realized how strange it felt to be awake… to be conscious, as if her body had momentarily forgotten how. Mimi slowly peeled open her eyes, her vision coming back in a very slow blur. She focused on the ceiling until her sight was clear again and tried to get some bearing on her unfamiliar surroundings.

 _Where am I…?_ Mimi thought to herself. She pulled the neckline of her dress up to her nose to sniff herself only to quickly release it at the odor. _And how long has it been since I’ve had a shower?_

Mimi sat up on one arm to scan the rest of the room as it appeared in her field of vision, her back sticking slightly to the sheets from sweat as she retracted from them. The area was incredibly messy, and certainly a far cry from the couch she had originally been lying on in the time that she had become ill. A treadmill pushed against the furthest wall buried under a pile of dirty clothes and various food wrappers. A plain dresser in the corner. Even more clothes scattered across the stained carpet.

There was a light snore coming from the right of her, just barely out of her peripheral vision to prevent her from noticing anyone else’s presence sooner. Mimi’s eyes widened in surprise as a certain small statured skeleton sat in a very uncomfortable looking chair next to her. His arms were behind his head, propping himself up against the wall while one leg crossed the other in a lazy pose. He had his hood pulled over his face, probably to block out the light glaring through the window directly beside him. Mimi watched Sans for a few seconds, trying to process both his company as well as the absence of Aly. Mimi could have sworn it was her sister's voice telling her to wake up, and yet she was nowhere to be found. She must have still been dreaming.

Carefully, Mimi twisted herself in Sans' direction, making sure to remain quiet. She took in his form, paying attention to the features of his body, or at least what she could see of him under his loose t-shirt and baggy gym shorts. She had seen lots of monsters before, but Sans was the first skeleton. Was he built like a human skeleton? Were monster skeletons different? She studied the lines of his body, finding her eyes curiously drawn to all the points of bare bone. His shorts went a little past his kneecaps and as she scanned down his tibia and fibula, she found his feet were covered in a pair of warm socks and those fluffy pink slippers he always wore around the house.

Mimi giggled to herself, leaning down to take a closer look at them. She hadn’t really paid attention to his attire until now and found herself poking the slippers, trying to hold back laughter. A small and subtle bunny face was sewn into the tops, barely visible beyond the pink fluff.

“How did I not notice this before? They’re adorable,” she whispered, tracing the thread of the animal face with her index finger as she felt the soft fabric in between her other fingers. 

She poked the slippers one last time before a deep voice greeted her sleepily. “Kid…?”

Mimi glanced upward, meeting the dark sockets of the skeleton. Two pinpricks of light appeared in the dark holes. His expression rested somewhere between tired and baffled.

Mimi felt her body jolt as she quickly jumped away from the him. “Oh god, Sans!” she squealed, placing her hand on her chest and letting out anxious laughter. “Y-You scared me!” 

“S-Sorry,” Sans stuttered as he pulled his hood away from his head. “It’s just... you're..." He stared deeply into her eyes, as if still assessing the situation for himself.

"You're _awake_.”

“...That’s a surprise?” Mimi was more disoriented than she thought. Other than apparently foregoing a shower for god knows how long, she felt fine. Maybe a little weak with a fleeting hunger mixed in there… but fine.

Sans wavered. “Kid, you… you don’t remember?”

“Remember what?”

“Heh. Don’t suppose you would.” He let out an empty chuckle as he stretched himself out. “You’ve been completely out of it for days. If the infection didn’t kill ya, that fragile human body of yours would have shut down anyway.”

Mimi tensed up as she felt her stomach drop. “T-That’s nonsense. It was… just a fever…”

That’s the last thing she remembered of being awake.

Sans scooted the chair closer to the bed and hunched over the edge with a serious expression on his face. They sat in silence for a moment, just staring at one another.

The words finally slipped quietly from Sans’ mouth, painful like needles on their way out. “Mimi. Your heart stopped.”

Mimi rested frozen in her speechlessness. The words hadn’t quite reached her yet.

“Do you remember that?” Sans pressed on. “Do you remember anything _after_ that?”

“I… I _died_?” she finally spoke under the tremor in her voice.

“Yeah, I guess you did...”

“I…” Mimi shut her eyes and desperately tried to rack her brain for any memory of it. As hard as she tried, the last thing she could remember was falling asleep next to her sister on the couch during one of the rare occasions that Aly had decided to stay in all day. And as far as Mimi was concerned, that’s the best last memory of consciousness she could have asked for.

However, there _was_ something else. Something afterward.

“I remember… I was standing… in some sort of empty room.”

Sans’ brow creased. “What did you see?”

“Nothing,” Mimi recalled, disappointed in her own cloudy memories. “It was so dark… I couldn’t see anything—"

Suddenly, before she could reach the end of her sentence, another detail hit her. She didn’t even have to search for it this time.

“No! There was a light. …A bright light in the middle of all this darkness.”

Sans was silent, but staring intently into Mimi’s eyes as she spoke.

Mimi continued, “But… as much as I wanted to approach the light, I don’t think I ever made it. A voice stopped me before I could.”

“…A voice.”

Mimi nodded, still deep in thought.

“It didn’t sound like any voice I’d heard before, or even human at all for that matter. It was broken..." She paused, realizing how crazy this all must have sounded. This particular dream felt so far away from her now, and trying to piece the details of it together without embellishments was more difficult than she wanted it to be. "It told me that I was going to come back. I didn’t understand it at the time, but knowing that my heart stopped… I suppose it was right?" She grinned awkwardly at him, shrugging timidly. "Here I am.”

Sans remained quiet, even as Mimi uncomfortably shifted her gaze away from his.

“But… this all sounds insane, right?” She laughed nervously. “It’s just another one of those silly stories where people have died and swore they saw Heaven. I’m sure this was all just a dream that meant nothing. After all, dying can’t be _that_ black and white.”

“Kid…” A pained grimace flashed on Sans’ face for just a split second before he sighed and gave her his signature grin instead. “Of course it’s not black and white. Must have just been a _pigment_ of your imagination.”

Mimi caught an unexpected guffaw in her hands as she smiled back at him. “I’ve been awake for five minutes and you’re already killing me again with the puns!”

Sans gave her an aloof shrug. "Hey now, too soon to joke like that, kid. I just got you back." 

"Sans!" She laughed again as her smile grew wider.

As Mimi continued to giggle at their exchange, Sans pulled his own hand to his face, covering his eyes as if looking at her for any longer was too hard for him to handle.

Mimi noticed this and brought her laughter to a lull. “Sans…?”

“That smile, kid…” Sans mumbled under his breath.

Mimi became aware of the tint in his cheekbones changing to a light blue color. “Hey, are you okay?”

“Huh?” He hurriedly pulled his hand away from his face only to find Mimi just mere inches away now. Her scrutinizing inspection of his face only made the blue flush brighter. “W-What are you doing?” 

“Your face is blue.” Mimi continued to stare curiously.

Sans let out an audible gulp. “Y-Yeah, uh, about that—“

“Oh my gosh… do you… do you have a fever?!” Mimi reached up and placed a hand to his skull. “Are you sick too?” She flung the thick bed sheets off in one fell swoop and hopped out of bed.

Mimi was taken aback by her lack of leg strength from lying down for so long, but managed to catch herself on the edge of the bed before losing her balance completely. It was her second nature to be a mother hen - something she was always used to with Aly.

“Do you want to lie down? I can fix your bed and tuck you in and get you some soup or something if you want—” Sans could do nothing but watch as she began to scramble around the messy room. “Just tell me where everything is and I’ll—“

“Kid!” he called out in between his own bellowing laughter, grabbing her wrist before she got too far across the room.

Mimi whipped around, seeing the grin on Sans’ face. “I’m fine,” he replied. He began chuckling to himself once more.

“…What’s so funny?” she asked confused.

Sans let go of her wrist, placing that hand behind his head again and scratching his skull. “It’s just… you really do remind me of _them_. You’re just… a little too kind for your own good, just like they were. You’re too busy worrying about me that you haven’t even realized you’re up and walking around like you were never injured.”

Mimi looked down in shock at her bandaged leg. Sans was right; she hadn’t even realized she was no longer in pain now, not since they started their conversation. She sat back down at the edge of the bed and gently began to take the makeshift bandage and wraps off of her leg.

“Woah…” she gasped softly in astonishment at the light scar on her calf. “It’s healed...?”

Sans nodded. “You have your sister to thank for that. She went out and found some medicine for you. I'll give her that one - it's like she can work miracles when she's determined enough."

Mimi smiled at the thought of Aly. “She must have worked hard to get this for me,” she said quietly as she felt a slight tinge of regret lined in her gratefulness. “I have to thank her. Is she downstairs?”

“She’s out right now,” Sans answered bluntly. “She said she’d be back as soon as she could.”

“Oh…” Mimi felt a sudden sadness creep over her. A large part of her had hoped Aly would have been there the moment she woke up. Not that she was any less grateful for Sans, but Aly’s presence is what brought her the most comfort after these types of situations. It felt like ages since she had seen her sister.

Mimi could feel Sans keep his gaze on her when she averted her own back to the bedroom floor in disappointment. There was a pause, as if he were hesitating to find his next sentence.

“Hey, kid,” was all he managed to muster.

Mimi looked at him longingly for his next response.

He sighed again. There was a thin layer of what looked like a hurt expression in his small smile now; it was like looking at a wounded puppy. “Your sister was here all night with you, if that’s what you’re worried about.” He shut his eyes in thought, as if trying to tiptoe around the conversation. Mimi caught onto this.

“Where did she go?”

“She’s with Papyrus on his patrol right now.” He rubbed his hand against his head nervously before flashing his grin at Mimi. “They were going to calibrate some new puzzles he’s had in the works and needs a second opinion that isn't mine. You know, since they’ve hit it off so well recently.”

The dread that had loomed over Mimi vanished in an instant. Sans sounded genuine and she wanted to give him the benefit of the doubt, if only for the sake of her own piece of mind. She smiled warmly at him, who in return became a little flustered again.

“Thank you, Sans,” Mimi said happily, still smiling. She began making circles with her feet on the floor. “I really appreciate you sitting with me while she's out. I’m actually really happy she’s been enjoying herself, thanks to your brother.” Mimi scooted slightly closer to him. “Honestly, Aly doesn’t warm up to many people very quickly. It’s always just been us, so the only person she’s ever really been close to is me.”

Sans gave her a friendly nudge on the shoulder. “Hey, don’t sweat it. Your sister and I, we… understand each other. And I know she loves you very much.”

Mimi couldn’t contain her grin from growing. “That makes me so happy!” Without thinking, she reached for his hand and rested hers on top of it. “We’re so lucky to have friends like you and Papyrus.”

The blue in Sans’ face returned, even brighter than before. “It’s the least we could do, kiddo. And now we can get you home.”

That’s right. Mimi had nearly forgotten that this wasn’t their home. As much as it felt like it, as much as Sans and his brother had filled her recent days with so much joy, she and Aly were only visitors in their world. Their definition of home was ambiguous, but somewhere else - somewhere far away from here.

“R-Right…” Mimi’s gaze lowered. “Home.”

“Thought you’d be more excited than that.”

“I-I am! It’s just…” Mimi couldn’t quite find the words to say as she realized neither of them had moved their hands away from the other’s. “You've been so welcoming... and helpful. And even if we do nothing all day but sit on the couch and watch TV, or make full conversations from nothing but bad jokes... I feel closer to you," Mimi admitted. "So I-I… I think I’d miss you too much…”

Suddenly, Sans jerked his hand out from underneath Mimi’s, his eye lights shrunken down in surprise. Mimi sat stiffly in shock as well, her hand still hovering over what was now empty space.

The moment hung in the air between them.

Then the embarrassment hit.

“Oh my god.” Mimi could feel the heat burning in her cheeks.

Sans was just as flushed when he stood up.

“Oh god that was so stupid,” Mimi shook her head furiously as she buried her face in her hands.

"No, kid! I-It's alright—" Sans stuttered as he turned on his heels towards the door. "It's me. I just. I don't know if I—"

"Forget I said anything!" Mimi's muffled voice barely made it beyond her tightly clasped hands.

“Right. Uh. Hey. You're probably starving right?” Sans chuckled awkwardly, already trying to change the subject. "I'll run over to Grillby's and grab you somethin'."

Sans sped out the door and shut it loudly behind him before Mimi even had a chance to react. However, she was relieved to find herself alone in his room when she finally removed her face from her hands.

 _So stupid!_ Mimi groaned as she flopped back onto his bed in disgust with herself. What was she _thinking?_ How was she hoping Sans would react to that? Being this forward was so unlike her, but…

Something about this particular skeleton always lured it out of her, even if he wasn’t ever trying.

She could feel her chest on fire, burning with humiliation. Stupid, stupid, stupid. Now things were just going to be awkward.

But it's not like this would be the first time.

***

Mimi must have spent close to an hour in the shower, just letting the water (now cold, she had run the hot water dry twenty minutes ago) rain down on her face. She must have been clean by now, but the stench of spending days on her deathbed still felt plastered all over her skin.

The gravity of being awake had been weighing down on her now. Mimi glanced down at her hands, bones pushing taut against her skin. Her body was much frailer than she had left it after her last day of consciousness before the septic shock got the best of her.

 _I died._ That was the only part that she cold focus on.  _But I'm still here._ She looked down at the faint mark on her leg as water ran against where she remembered the open wound to be.  _Like none of that ever happened._

Mimi was suddenly thrown from her thoughts by a knock at the bathroom door that she could just barely hear beyond the running water.

"Hey, kid?" Sans' muffled voice called out from beyond the door.

 _Sans!_ After his abrupt exit, Sans had left the house for quite a while. The truth was that Mimi actually  _was_ starving, but he had taken so long to come back that she settled for what leftovers she could salvage from the refrigerator.

"Yeah?" Mimi shut off the water to hear him better. It was probably time to stop wasting their water anyway.

"Brought you something to eat. But, uh, take your time in there."

"Thank you!" Mimi shouted as she dried her hair with a towel before wrapping it around her body and stepping out of the glass shower and into the bathroom filled with clouds of steam and moisture. As embarrassed as she still felt to face Sans, she was also still hungry. Catching up several days worth of meals was no easy feat.

Once she was sure that Sans had gone back downstairs, she carefully cracked the door open before securing her towel and slipping back into his room as quietly as she could. As soon as she shut the bedroom door behind her, her nostrils were met with the overwhelming aroma of hot food. 

On the dresser in the corner of the room sat a neatly tied plastic bag with a card addressed to Mimi in large, curly letters sitting on top of it.

With hair still dripping, Mimi picked up the card and flipped it open.

_"Glad to hear you're alive and kickin', sweetie. You had all of Snowdin worried there for a second. Stop in when you feel up to it again. In the meantime, eat up! -Fuku"_

Mimi smiled as she excitedly untied the bag. Inside was a styrofoam box filled with a hamburger and fries, another container packed with four cinnamon bunnies, and a small paper bag filled halfway with assorted hard candies.

"Everyone cares so much..." Mimi's heart felt so full. Even people that barely knew her were worried about her.

If this wasn't what home felt like, then she didn't want to know its true definition.

Before digging into the assortment in front of her, Mimi glanced over at her dress strewn across the bed. She  _really_ didn't want to wear it again without washing it first. As wary as she was about her next course of action, she scrupulously opened the top drawer of Sans' dresser. It was stuffed with unfolded t-shirts in varying styles and colors. She grabbed the first one on top, a plain white one, before opening the bottom drawer and doing the same with a pair of shorts. Mimi giggled when it occurred to her that the outfit she had haphazardly picked was identical to the last one she had seen him wearing. Hopefully he wouldn't mind.

As Mimi draped the towel against the chair that seated Sans earlier that morning, she found herself simultaneously getting dressed while scarfing down food from the bag. Shirt on, a handful of fries. Shorts on, a bite of the hamburger. Hair up, half of a cinnamon bunny down.

To her surprise, Sans' clothes actually fit her quite nicely. Even though he was smaller than her, she noticed some of his outfits still tended to be baggy on his thin figure. Somewhere in the size difference, this balanced itself out to the shorts hitting a couple of inches above her knee and the cotton shirt being just loose and comfortable enough for her petite torso.

Mimi brushed off the crumbs that had already fallen onto the shirt from her hurried eating, then packed the rest of the food neatly in their containers and tied the bag up. She figured that Aly would probably want some when she came home from her time with Papyrus, so she decided to store the rest in the fridge for later.

 

The bedroom door creaked open as Mimi tiptoed across the hall and down the stairs with the food in hand. However, she stopped mid-step when she heard Sans talking in the kitchen.

"She hasn't been that way at all?" He must have been on the phone. Mimi remained frozen in place as Sans continued his hushed conversation. It was just loud enough for her to make out his words, but not the ones of the person on the other end.

"Look, she can't get very far on foot. Are you sure the River Person hasn't seen her?"

A pause.

"Well just _try_ , okay bro? Her sister's awake and you can't show up without her."

Another pause. Mimi was quick to put it together; Sans was talking to Papyrus. And Papyrus was not with Aly.

Sans was being caught in his own lie.

"We'll think of something if you can't find her. Sorry you got caught up in all of this, Paps. See you soon, alright?"

 The conversation seemed to end with the sound of Sans sighing followed by the clicking of his cell phone being tossed onto one of the kitchen surfaces.

 _He's lying to me._ Mimi clenched her fists as she stomped down the rest of the stairs in his direction.

Sans still didn't notice her when she appeared in the kitchen entryway. His back remained turned to her as he leaned over the counter, moisture from the snow outside still saturated into the black jacket and jeans he had changed into. Her resounding presence as she entered and loudly threw the bag she was holding onto the round breakfast table finally startled him.

"Kid!" Sans spun around. "Y-You scared me."

Mimi didn't respond. Instead, she stood stoically in front of him with her arms crossed.

Sans tried to grin, but faltered. "What's  _eatin'_ ya? Heh."

Still no response as Mimi could feel her emotions manifesting themselves into tears at the corners of her eyes. 

"Where's my sister?" She finally choked back the tears enough to ask.

The expression in Sans' face was a clear indication that he now realized that she had heard his phone conversation. And yet, he _still_ tried to hide it, almost testing Mimi's knowledge. "I told you, kiddo. She's out with my brother."

"...Please don't lie to me." Mimi was shaking now. How could he do this to her?

"I wish I had a better answer for you than that."

That's when she couldn't hold back anymore.

"You and Aly are so alike," Mimi sobbed. "You think I don't know things, but I do. Being around my sister, I've dealt with it my entire life. You keep things from me, thinking it's for my own good. You bury it so deep that you hurt yourself, thinking you're doing me a favor." Her volume was growing louder and louder with every word. "But I'm here! I see. I care. So don't push me away, you jerk!"

"That's not—"

Mimi didn't even want to listen to him at this point. She stormed out of the kitchen, but didn't make it very far before stopping in the middle of the living room. It was almost as if she wanted him to follow. 

And so he did.

"Mimi, please." 

Mimi hugged herself as she stood at the center of the empty living room space that seemed far too large now, too upset and too embarrassed to face the skeleton.

"You know as much as I do." Sans gingerly stepped closer to her as he spoke. " _Tibia_ honest... your sister doesn't like me very much. Actually, I'm pretty sure she doesn't like me at all. You must have caught on to that much. But she's gotta have a reason for acting like this. After all, she's the reason why you're still here."

"So are you..." Mimi whispered quietly between sniffles. She didn't want all of Sans' help to go unnoticed.

The statement made Sans chuckle once. "That's where you've got it wrong. I'm the reason you died."

The sadness was building in Mimi's chest as she turned to face him. He stood only inches away from her, head tilted up to meet her gaze.

They stood in silence once again as Mimi felt Sans' invisible hold on her returning. His expression, almost completely buried behind the large fur hood of his coat and a wool scarf, was one of pain. Maybe nothing that Mimi herself had inflicted, but an underlying hurt that was now surfacing in the lines and cracks of his skull.

Without saying a word, Mimi reached down and pulled Sans into an embrace, wrapping her arms around his neck and burrowing her face into his shoulder. She could feel him tense up under her touch, not so much as moving a finger while she held him.

Against her better judgement, she stayed like this for another long moment before finally letting go. "I-I'm sorry..." She let out a little laugh at herself as she wiped away the rest of the tears. "I don't know what's gotten into me lately. I guess... I don't want you to feel as worthless as you like to make yourself out to be. Thank you... for telling me the truth. I'll just go back upstairs and leave you alo—"

"Kid."

Before Mimi could even process another thought, she felt the thud of Sans' body hitting hers, his short arms wrapping around her back as far as they could reach. Blood was rushing to her face as she felt the ridges of his bones underneath his wrinkled dress shirt; its misaligned buttons messily secured to the wrong button holes. Until now, she had never been close enough to notice that he was  _warm._ Beyond the layers of winter clothes, his bones resonated with the same warmth as another living, breathing creature. They were so different, and yet the warmth of simply being alive was something they shared.

"You want the real truth, kid?" Sans' voice cracked as his grip tightened. "When things started to look bad, I couldn't handle it. I couldn't lose another human I cared about again."

"Sans..." Mimi whispered under her breath as she felt the tears she had just wiped away returning.

"So I tried to force myself not to care. I reminded myself, _'don't let yourself get too close.'_ But you were just like them. Too much like them. Dying... just like them. So I'm sorry, okay?" Sans was beginning to chuckle again, low and somber. "I gave up, because that's all I know how to do."

All Mimi could think to do was reciprocate Sans' embrace even tighter as she gathered herself around his words. Should she have been more upset with his confession? Was all the time they spent together up until this point really as empty as he made it seem? She wasn't going to believe that.

After all... her feelings for him were real. Mimi refused to think that these emotions were misguided just because Sans was good at hiding his own.

"What was... their name?" she asked.

"...Does it matter?" Sans retorted.

"Everything matters to me, especially if they were this important to you."

Sans hesitated, but finally ceded to Mimi's question. "Frisk."

Somehow, finally having a name to this vague figure of Sans' past was comforting. They felt real, indispensable. It gave Mimi the jumping off point she needed. Because in this moment, something was different. Sans had always kept certain reservations, but the walls were coming down.

And Mimi wanted to be there to catch him if they collapsed.

"Well then... I'm glad... I'm glad I can remind you of Frisk."

"Spare me, kiddo. I don't expect you to forgive me."

Mimi laughed in between the tears streaming down her cheeks. "There's nothing to forgive, you _bonehead_. I'm here because I want to be."

They held each other in the middle of the living room, surrounded by nothing but vacant space and silence. All of Mimi's previous emotions were beginning to melt away. The sadness, the confusion, and the embarrassment all slipping into nothing under the feeling of Sans' bones against her skin.

"So am I, kid," he spoke softly into her ear. "So am I."


	11. The Power of Determination

**Summary for the Chapter:**

> Aly learns more of her parents' whereabouts than she was intended to. Gaster begins his experiments. The twins must decide what to do next.

**Notes for the Chapter:**

> Confirmed: Gaster is an asshole. ~~We should really change the pairing tag to W.D. Gaster/Science because that's the OTP here.~~
> 
> Anyway, this has been an extremely overwhelming last few of weeks for the both of us. But we hope the fact that this is our longest chapter yet makes up for it a little. :') And with convention season upon us, the next month or so is going to be a little slow for writing too. The flip side is that less writing usually means more drawing! So be sure to get an Undertaken refresh on our [Tumblr](http://anundertaleoftwosisters.tumblr.com/) in between chapters.

As promised, Aly returned to the hidden door in Waterfall. She hesitated slightly as her fingers grazed its metal doorknob, the glimmering stones of the dark cavern walls reflecting off of its surface. She wondered to herself if anyone else had stumbled upon this peculiar door in the past. It wasn't too far off of the path and not as well hidden as one would expect for something so out of place to be. Aly couldn't have been the first to find it, and she most likely wouldn't be the last either.

After a composing breath, Aly pulled the door open just wide enough for her to slide through and shut it quietly behind her. When it closed, the room became devoid of any light, just as she remembered it from the first time. She realized now that it was more than just the absence of light; it was as if the darkness were actually devouring it.

Even though the darkness was blinding, Aly heard a familiar broken voice whispering to her from across the abyss. It spoke with an endearing tone, though she couldn't understand it.

"Doctor," she acknowledged, regardless of failing to translate his words.

Suddenly, a light flickered on in the distance. The source of the illumination was coming from atop the desk that Aly could barely make out from the shadows before. It was a dull, gray glow that struck a fleeting feeling of deja vu in her chest while it cast light onto the tall figure standing in front of it, still dressed in the same black robes. The figure turned around and beckoned her over with an outstretched hand.

Cautiously, Aly approached Gaster. The space between them was much farther than she perceived. The room felt much larger now, but Aly accredited that to her nerves. With each step, she felt her body temperature dropping. She began to shiver, but wasn't sure if that was from fear as well.

"I'm so glad you decided to return." Gaster's tone was still soft as his two dominant hands wasted no time in signing each letter out. While there were many times when she would miss a few symbols, Aly was still bewildered with her own abilities to keep up, as if it were a language she had been studying for years.

"Thank you for helping my sister." Aly was in front of him now. "I don't think she would have made it another day without you."

"Most likely not," he boasted. "I am aware of how important your sister is to you. So I hope you'll respect how important what comes next is to me."

The concerned grimace on Aly's face was clearly readable, even in the shadows.

Gaster was quick to notice this. "Please, make yourself comfortable." He gestured to another surface just to the right of the desk - yet another object Aly hadn't even noticed before as her eyes struggled to adjust to the lack of light.  When she approached it, she realized it was the same height as the desk, so she pushed off the ground slightly and pulled herself onto it. It’s cold, steel surface startled her at first. Some sort of examining table.

"Is this your lab or something?" Aly asked, trying to make out the shapes of even more black silhouettes. On the wall furthest away from her were the outlines of many large machines, tubes and wires dangling from the ceiling. Shelves on the wall closest to Gaster's desk housed an assortment of glassware and books.

"I suppose you could call it that," Gaster let out an amused chuckle. "It's dreadfully outdated, but I haven't met any humans as willing to supply me with equipment quite like your mother and father did all those years ago."

"My... parents...?" Aly cocked her head curiously. "What did they have to do with this place? And..." She continued to move her eyes around the dark room. "What  _is_ this place exactly?"

"Your parents coined the vernacular for this existence. _The Void_ , they called it," Gaster explained. "Somewhere in between the living and the dead; beyond the darkest corners of the absolute. A place that no living soul may enter unless they're... invited."

Aly was struggling to keep up with his signing as she contemplated each of his words as they came. "Are you saying that... you're not _alive?"_

"Not in the way that you perceive it, my dear." Gaster reached for something on the desk behind him before approaching Aly where she was seated. In his hands he held what looked like a thin leather-bound book. "I am alive in the same way that you sit here before me," he continued. "But my existence is tethered to this space. I am not a part of the world out there in the ways that you are, therefore I cannot leave."

Aly had so many questions. But before she could bring any forward, Gaster set the book on her lap. "When your mother and father came to the Underground, they found this place the same way you did. It had been ages since I had contact with a human being, let alone other scientists. We shared our knowledge, our research, our stories. And they kept all of those experiences in this journal, which I suppose rightfully belongs to you."

Aly's eyes widened. Her heart sank to her stomach as she felt the worn leather under her fingertips. 

"T-This..." Her voice shuddered as she hurriedly pulled sheets of paper that she kept folded inside of her skirt pocket all this time. As she unfolded them, the pages revealed the map of Mt. Ebott and the miscellaneous journal entries she had salvaged from her parents' previous journal after the fall. It was all useless information, but held a sentimental connection that she wasn't quite ready to let go of. "This is where they left off."

"You and your sister were right to come to the mountain," Gaster affirmed. "This was indeed the last place they existed."

Gaster liked to throw around that phrase a lot: _to_ _exist._ As if it were not just something that came naturally with being alive. As if one could never truly exist beyond the Void. The layer of dread hovered over Aly. What became of her while she was here as well, then? No, that wasn't the important question. For both her and Mimi's sake, she had to focus on their parents while Gaster remained on the subject.

Deep down, Aly knew they were gone. She never expected to bring them home, regardless of how steadfastly Mimi held onto that hope for years.

She tightened her grip on the journal as she cradled it to her chest, holding what may have been the last piece of them that she would ever touch. Suddenly, it was becoming more real.  _They_ were becoming real - more than just foggy memories in the back of her mind.

_That's right._

"Gaster..." Aly stated hesitantly. "Did the fact that we couldn't remember them... did it have something to do with this place? With you?"

Gaster's thin grin spread across his face. "You are very perceptive, darling. Just like your father."

"I just want answers." That's all she's ever wanted.

"The short answer is yes," Gaster signed. "However, like your father, I assume you won't be satisfied with just that."

Aly shrugged. "We were young. You probably knew him better than I did."

"Right, I suppose so." Gaster turned his attention back to the desk. Now that he was positioned differently, Aly was able to see more of the contents resting atop of it. Blueprints, stacks of handwritten notes, and vials of glowing liquids similar to what he had supplied for Mimi's treatment. All of these things were still encompassed in the dim glow coming from a glass container at the corner of the desk.

_The heart._ The one she had seen in her dreams. There it sat in the container, beating ever so slightly to a weak rhythm and emitting the same light that led the way through the dark in her sleep. However, upon further inspection, it wasn't exactly the same as she remembered it. Hairline cracks ran along its porcelain surface and revealed a layer of black splotches underneath. They were subtle, like old ink stains on a gray shirt. Unlike in her dream, it was imperfect; flawed.

"Your mother and father were charming," Gaster continued as his attention was turned away from Aly now. "Their eyes were filled with so much wonder when they arrived down here to help the monsters eagerly awaiting the moment they could become citizens of the Surface. They worked very closely with the King’s Royal Scientist in making sure monsters were prepared for the world outside." The rustling on his desk ceased. His hands faltered. "All the while, I was here. And all I could do at the time was watch their curiosity of our world unfold."

"But they found you eventually," Aly exclaimed.

“Correct. Not even fear outweighed their fascination with my existence."  Gaster was back to fiddling at his desk, taking many of the colorful samples in the vials and mixing them together in an empty beaker taken from the shelf. “As the Underground emptied and the rest of their team returned home, they remained here to learn more about my work, all of which was cut short when my life in your timeline ended."

Aly still wasn't going to pretend that she understood what Gaster meant by that. Add another line to the unending string of questions she had now. However, she continued to sit silently and just listen. She hoped that giving the doctor enough time to explain many of the gaps she couldn't fill in would suffice in her quest for answers.

"They were almost _too_ kind. Too trusting, too curious. By the time I had relayed all of my knowledge to them, they had grown... rather sentimental. They pitied me. And they swore they were going to accomplish one more thing before they headed home."

A long drawn pause as the doctor was getting lost in his own words."They were going to pull my soul from the Void, a feat that not even I could figure out."

"I-Is that possible...?" Aly stammered. 

"We're still here, aren't we, darling?" Gaster retorted. It seemed the doctor had a sarcastic side as well.

"We ran as many simulations as we could with such limited resources. When all the monsters had been cleared out, they transferred as much equipment here from the Royal Scientist's laboratory as they could. We successfully reconfigured many machines to fit our needs. We spent countless hours doing more research, more calculations, more trials. But each attempt was just another failure."

"However, they remained determined. And that's when we created  _it._ " Gaster gestured towards the beating heart in its glass encasement. Aly looked on in awe.

"The very first artificial soul, infused with the core essence of my being. They wouldn't be able to pull me out in a way as simple as walking out that door, but it was a start. If we could just attach this new soul to a vessel, I would have a chance to _see_  that world again. To hear, to smell, to feel... To put the pieces of my former life back together, perhaps find my family. Every part of me that had disappeared, regained - just not in this form."

One detail stuck out in particular. “...You had a family?” Aly’s eyes widened. It never occurred to her that a figure as enigmatic and cloaked in mystery as Dr. W.D. Gaster _did_ have a normal life before the Void.

"Sons," Gaster answered somberly, dropping his hands. "That I would have given anything to see again."

Silence stood stagnant in the air for a moment before Gaster composed himself once again to continue his formal explanation without a trace of melancholy left in his tone.

"We kept trying, despite the failures. However, after coming to the definitive conclusion that this new soul would not adhere to another host, monster or otherwise, your father was the one that offered the hypothesis that perhaps attaching it simply wasn't enough. It must be completely fused with another existing soul."

Most of this information was going over Aly's head now. However, she tried desperately to grasp what she could out of respect for not only Gaster, but for her parents, who apparently held this with such high importance that it delayed them from returning to the Surface.

Aly pulled her drifting mind back when she realized Gaster had not stopped his explanation. She focused on his hands again, reading each word two letters at a time.

"You see my dear, you humans are so incredibly lucky to have souls that are predisposed to certain traits that grant you an immeasurable amount of strength. After centuries of researching these traits, monsters have been able to isolate them and convert them into magical energy. That is what has made it possible to harness these traits in various ways - such as healing purposes. And each trait grants unique capabilities: Patience, Bravery, Integrity, Perseverance, Kindness, Justice, and Determination."

Her heart skipped at that last trait. This had to be what Sans had mentioned before, meaning he knew about human souls and the importance of Determination, even if Aly still did not.

Aly's understated patience was paying off as Gaster continued to answer all of the burning questions that were building up in her mind. "Monsters have the ability to see the dominant traits within a human soul by using their magic. And a human soul with Determination was the only type strong enough to withstand this experiment the three of us had put together."

Aly felt the hairs on her neck stand on end as he shifted closer towards her. In one hand, he held a new, larger syringe filled halfway with a bright red liquid. She clutched the journal in her lap tightly, almost like a crutch to her now. Her body temperature was lowering again, sending shivers through her spine and all the way down her legs. Closer and closer he approached, the grin on his stark white skull cutting through the Void. Gaster was clearly prepared for what came next - Aly was not.

Gaster extended his free hand and hovered it over Aly's torso. His closeness made her uneasy, but she stayed as still as she could.

Suddenly, there was a tugging sensation in her chest. She let out a startled gasp as she looked up at Gaster for answers. In response, his gaze returned down to his hand.

And there it was, radiating a blinding red glow against Gaster's bones.

"As I expected," he hummed, pleased. "So  _perfect_."

"I've never... seen anything like this before..." Aly looked down in astonishment. Another porcelain heart revealed itself outside of her own body, beating in sync with her breathing.

"This is your soul," Gaster explained. "And your predisposition to the trait of Determination is... remarkable."

"You can tell just by looking at it...?"

"The color is the sole indication." He gestured around the soul gently. "There is no mistaking it."

"And... this a good thing?"

Gaster let out a single chuckle. "It is precisely what I have been searching for, darling. Now please, if you could lie down, we'll get started."

 

The uncomfortable coldness of the steel table prevented Aly's muscles from relaxing. On top of that, Gaster had been hovering at her side for what seemed like an eternity, staring at her exposed soul with a glimmer of wild fascination in his good eye. Was her Determination really that important? Even being aware of it now didn't make her feel any different. She didn't feel... determined? Or however her predisposition was supposed to make her feel. 

"I guess I'm still a little unclear about what you need from me," she finally spoke up.

"That will all be explained very soon, darling. For now, I just want to test the strength of you soul."

Aly glanced uneasily at the syringe, still in Gaster's hand from earlier. "Then... what is that?"

"This is what Determination looks like when extracted from a human." He held it up to the red glow of her own soul, the reflective red liquid catching in its light. "As you can imagine, I have kept this sample for a very long time. You are the first red soul I have encountered since your father."

It was easy to put the pieces together after that. "Then that means..."

"Correct."

Suddenly, the repercussions were becoming too overwhelming. That was _his_ Determination. The last existing essence of her father's soul. And regardless of what Gaster intended to do with it, Aly was no longer interested. "I-I don't think I can do this—"

"You must."

"I _can't_." Aly's instincts were kicking in. She bent her knees in preparation to push herself off and run. There was nowhere  _to_ run, but that wasn't going to stop her from trying.

"I apologize if it was unclear that this is not a matter of choice," Gaster's voice rumbled callously.

He was too perceptive; always a step ahead. As if reading Aly's thoughts right out of her mind, he summoned several more hands in one fell swoop of his magic and used them to restrain Aly's arms and legs to the table.

Aly gasped as she struggled against the hands to no avail. "Y-You can't make me do this!"

"You volunteered, remember?" Gaster was detached, mirthless. "Just as your parents did."

The syringe was coming closer into view. She turned her head away when it was too close to her face for comfort.

But suddenly, there was another hand underneath her chin, forcing it back into place.

Aly's heart was beating out of her chest. Not her soul, her real one. Her frenetic breathing was quick and anxious. "W-What are y-you—"

With a dominant hand, Gaster forced her left eye open and centered the tip of the syringe over it. "What's that saying you humans have?" he mused. "The eyes are a window to a person's soul?"

"I-It's figurative..." Aly spat, even though she was fully aware that Gaster had his elaborate reasons.

Not that he intended on sharing them. "Well, I suppose monsters never  _were_  good with such abstract concepts."

With that, Gaster drove the needle of the syringe directly into her cornea and injected every drop of the liquid.

Aly felt the effects immediately. Her body, still being held down by Gaster's magic, was going into shock. She thrashed and convulsed furiously as her blood-curdling screams were lost to the Void. Her entire face was on fire, as if the injected eye was melting out of its socket. She looked over to see Gaster still hovering over her, expressionless through each scream she let out. How could she have deluded herself into thinking he cared about her or her sister at all? In this moment, she  _hated_  him. That hatred in her soul burned just as intensely as the physical pain she was feeling. Boiling tears rushed down her face until darkness overcame everything.

 

Beyond the dark, a muffled female voice was speaking. It was vaguely familiar, and yet Aly couldn't quite place it. As she blinked her eyes open, the voice became clearer and clearer.

Something was off.

The setting that came into her view wasn't the Void. In fact, she was standing at the edge of a sterile white room with tiled floors. The brightness was staggering, but once her eyes adjusted, she could see everything more clearly. It was a laboratory, filled with familiar machines and equipment - all of which Gaster had in his possession now.

"Do you think the doctor would need this?" The female voice's came from behind Aly.

Suddenly, Aly's body was moving without her authority. It turned around to face the owner of the voice - a woman in her thirties, wearing a long white lab coat and her chestnut brown hair in a messy knot resting at the very top of her head. Her features, so soft and gentle, sparked Aly's memory immediately. She looked almost identical to Mimi.

_Mom._

Another surprise hit her as a male voice came from her position. "Only what you can carry this time, darling."

_Dad...?_

Okay, something was  _very_ off. The realization that Aly couldn't actually move or speak on her own accord crashed over her like a wave. And once she glanced down, she realized that her body was never hers to begin with. This was all some sort of lucid dream; a dream in which she was merely a spectator. 

And for some reason... in her father's place.

The woman, her mother, continued to sift through drawers and loose equipment on the counter behind them. "Dr. Alphys won't miss these, right?"

"Trust me, Cath," her father chuckled. "I don't think any monster is going to come around here again for a very long time. If she didn't take it with her, she won't miss it."

Just as Aly felt the desire to try and speak, regardless of how futile it may have been, the world began to stutter without warning. Like a glitch in a computer program, the world in front of her began to inexplicably shift.

 

Before she even had a chance to blink, Aly was in darkness again - the brightness of the previous setting was still imprinted in her vision. However, it wasn't complete darkness this time. The dim light of an office lamp illuminated a small circle of the area, revealing a desk stacked with papers and blueprints. The voices were speaking again. She was still dreaming.

"I'm confident that this will work." It was her father's voice, coming from the body she was involuntarily inhabiting.

Then her mother's, "Derek, don't be ridiculous."

And then a third voice, broken yet familiar. Hands flashing symbols in the dim light, though Aly couldn't see a face. She didn't have to.

"What is he saying, Catherine?"

"Dr. Gaster thinks your hypothesis is correct. And... he wants to move forward with it."

"I guess that's settled then." He clapped his hands together.

"Derek, shouldn't we think this through a little more? It's not like we have human souls at our disposal to run these simulations on—"

"We only need one. Mine will do."

"Y-You can't be serious."

"Please trust me, darling. This is going to work. Go ahead and write a letter to the girls tonight. Tell them it'll just be a little while longer and that things may be a bit... different... once we arrive home."

 

The world stuttered one last time.

This time, it placed Aly in the middle of chaos. She was on a table - the same one she actually remembered lying on. However, she still had not regained control over her own body. This still wasn't real.

But this time it  _felt_ real.

"We've failed, Gaster! Reverse the machine!" The sound of Catherine's cry rang through the abyss over the strained hum of a machine Aly could not see. All she could see from her vantage point were shadows cast by a bright red glow coming directly from her chest.

Her soul?

_No,_ Aly reminded herself.  _His soul._

"We can't," Gaster's voice hissed audibly from the shadows with no translation needed.

"You're killing him!"

"There is no turning back."

"You HAVE to!"

The glow of the soul suddenly vanished. Only the sounds of screaming, crashing, and glasses breaking remained. Gaster's untranslated words became hostile, then remorseful... then desperate.

And then nothing.

 

There wasn't any doubt that Aly was really awake this time, thanks to the immense pain still resonating from the entire left side of her face like a slow burning flame against her skin. When she reached up to touch the source of the pain, she realized that her eye was covered in bandages.

The darkness had subsided enough for her to see her surroundings through her remaining eye. She was uncertain whether that meant her vision had adjusted to the Void, or that the darkness itself was tangible like a dense fog that had momentarily lifted. Regardless of what it was, Aly could finally see the exit that she couldn't locate before. She could see Gaster's desk right in front of her. Most importantly, she could see Gaster, hunched over beside her as he scribbled notes on paper rapidly with his hovering hands.

"The results were not as strong as I had hoped," Gaster exclaimed flatly after acknowledging Aly's consciousness without even glancing up at her. "It appears that your soul was... resisting. But it's no cause for concern - we will compensate for that later." After jotting a few more lines of notes, the doctor turned to her.

"How do you feel?"

Aly didn't respond. Her only honest answer would have been that her skull felt like it was split in two. Or that the lingering pain from before she lost consciousness was still so strong that her entire body felt too sore to move. That her throat was so ragged from screaming, she was sure no words would come out even if she had tried to speak. That the visions she had just seen of her parents were still so fresh in her mind that she couldn't wrap her energy around anything else except for despising Gaster for doing this to her. No, more importantly, for doing this to  _them._

When Gaster reached one hand over towards her, Aly's body instinctively shot up from the table and jolted away from his touch, ignorant of the throbbing pain in her joints and muscles.

"Don't touch me." As expected, nothing but a hoarse whisper left Aly's mouth.

 Gaster flinched, visibly taken aback by Aly's gall.

"Don't come near me ever again," she wheezed with all the strength she could muster.

"But we haven't even started, darling."

Aly recoiled at the endearment, now obviously stolen from her father. "Do  _not_ call me that."

"My, that's quite the list of demands." Gaster's voice lowered. "But please don't be difficult. We're going to finish this."

Aly gingerly made her way to her feet, catching herself on the edge of the table when she felt herself losing balance. All the while glaring through the doctor's dark and empty eye sockets.

“You _killed_ them. I _saw_ you," she hissed on each emphasized word. "You murdered my parents for your sick, failed experiments. I-Is that what you planned on doing with me too?"

"Ah, very interesting..." Gaster's tone shifted to the sound of pure intrigue, his hands slowing down as he became more encapsulated in his own thoughts over translating for Aly. "Your father's Determination must have held some residual memories that got transmitted to you through the injection."

Aly didn't care about anything he had to say anymore. "Answer my question. Is  _that_ what you needed me for? ...To take my father's place?"

"That was a long time ago. Your parents and I... we failed because of our lack of understanding. But I have not taken that failure lightly. I am confident in my abilities, I have just been waiting for the right human to come around again."

"What about what I want?" her voice shook against the physical strain of forcing out cracked words. "I... I can't die. I have someone that needs me... Someone I'm not allowed to die on!"

Gaster took a single step towards her. "When we succeed, dying will be the last thing you have to worry about, my dear."

And another step. "And of course I care about what you want. That's why I saved your sister, isn't it?"

With one final step, he was now towering over her. "Remember, it could have easily been Mimi standing here instead of you. I imagine Determination runs in the family. This will happen one way or another."

"I'm not afraid of you." Aly lied through the tremor running through her bones at the notion that Gaster would stoop so low as to bring her sister into this. She could almost convince herself that she were brave enough to stand up to him, but in reality, she had never been more terrified of anything or anyone in her entire life. It was a new level of fear that she never knew existed. 

“Courage does not equate to control.” Gaster's voice was a deep, guttural growl now.

After allowing a moment to pass in unnerving silence, Gaster finally straightened his stance and pulled the familiar black journal from behind him.  "If you truly insist on leaving today, then let me remind you of two things." He placed the journal in Aly's wary hands.

"First, your time here remains private."

Aly reached for her face again, fingers met with the padded cotton over her eye. If she were to comply, and she was in no position to refuse, she needed to think of something to tell Mimi and the others back in Snowdin.

"And second," Gaster started as he gestured towards the exit.

"There is nothing you can do to stop this from proceeding."

Without any strength left to answer the daunting figure before her, Aly staggered to the exit as fast she could and bolted out, never looking back at him. She slammed the door behind her and began to run. She ran in the direction of Snowdin, and then in no particular direction at all. After reminding her frantic mind that he wasn't capable of following her, Aly stopped and collapsed to the ground in the vaguest sense of relief. However, she was already aware of his omnipresence. Even if he didn't follow her, he was still watching.

She found herself lying in a field of echo flowers that were strangely silent. But they wouldn't be for long, as Aly could no longer stifle the tears she had held in for so long while trying to stand her ground against Gaster's threats. She sobbed so uncontrollably that the echo flowers all mimicked her until their sounds turned into white noise and eventually reverted back to silence. Over, and over, and over they went in this circle, until even the flowers had more tears to cry than she did.

***

After a long time alone to try and calm herself, Aly arrived back in Snowdin later that evening. She wasn't ready to face everyone just yet, but she knew it was unavoidable. If anything, seeing Mimi was all she needed right now. Making her way through the snowy town, it wasn't long before she reached the cozy wood-paneled home belonging to the skeleton brothers. She swallowed nervously. Sans, sitting leisurely on the front porch in his collared shirt and jeans, shot up when she came into his view.

When Aly was finally close enough, she stopped in front of him and stared intently before he could say anything. “Sans… how is she?” Her voice was returning, though still hoarse.

“She’s awake.” Sans' eye sockets were dark. “...What the hell happened to you?”

Aly couldn’t gather the words to explain it to him, even if she wanted to. All she could think about was seeing Mimi. When she passed Sans and reached for the front door, he grabbed her wrist as her hand met the knob. 

“Aly.” His voice was rigid.

“I-I… need to see my sister, Sans. Please.” Aly couldn’t even look at him. She could feel her chest tightening as she fought the overwhelming desire to break down and cry again.

Sans loosened his grip and conceded as she pushed her way through the door. Just like that, Aly felt relief wash over her as she saw Mimi sitting on the couch, attention glued to the TV in front of her. There was also a faint burning smell in the air; Papyrus was cooking dinner in the kitchen.

It took a moment for Mimi to notice her standing in the doorway, gazing in awe through her remaining eye at her sister's healed condition. When Mimi finally turned her head, the unexpected sight of Aly froze her. And for a split second, elation spread across her face. However, it quickly changed to distress when she examined Aly.

“Mimi!” Not giving Mimi a chance to react, Aly dove onto the couch and hugged her sister. Her arms grasped her tightly and she suddenly felt everything she had went through thus far was worth it. This was the first time she had seen her awake in days. Right now, she was thankful. She just wanted to be happy.

“A-Aly!” Mimi reluctantly tried to return the enthusiasm. Her hair was still in wet knots from a recent shower and one of Sans’ t-shirts hung loosely from her torso.

“Oh my god, I can’t believe you’re awake.” Aly’s voice quivered in excitement. “You’re okay. You’re really okay.” Her  grasp on Mimi tightened even more with the fleeting happiness she could manage to feel beyond the pain. After almost losing her, seeing Mimi alive, seeing her moving around... it was a miracle.

When Mimi finally pulled herself away from the embrace, her eyes widened when she caught a closer view of Aly’s bandaged face. “Aly, what—“

Aly instinctively turned her head away, but Mimi worriedly forced it back with her hands. Aly felt her sister's fingers slowly graze her skin as she inspected the cotton clad area.

“Aly… what is this?”

“Nothing.” God, why couldn't she come up with anything to tell her?

Mimi scrunched her face at her sister’s terrible answer as she began to gingerly peel the bandages back, not even asking for permission to do so. Aly winced each time the medical tape near her eye caught her skin, but didn't stop her sister from continuing. Although she was completely at a loss for what to say to Mimi, Aly felt a strange sense of comfort in her sister's concern. It was just like how things used to be.

When it was completely removed, Mimi let out a sudden gasp.

“Is it… is it bad?” Aly asked sheepishly as she blinked a couple of times. She had no idea what the physical effects of the injection were. However, her heart sank when she realized her vision was still completely gone from that eye, even after being uncovered.

Aly saw tears forming in Mimi’s eyes as she softly cupped her damaged face. “Oh my god, who… who did this to you...?”

“I don’t know what you’re—“ Aly glanced over at Sans, still standing by the door. When their gazes met, even the lights in his eyes shrunk to pinpricks. 

“H-Hey, kid,” Sans addressed Mimi but kept his eyes fixed on Aly. “Why don’t you take your sister upstairs? Get her cleaned up.”

“...Right.” Mimi nodded as she shot up from the couch and pulled Aly up as well. Aly was surprised at how agile Mimi was now that she was awake again. Going up the stairs, which was previously a challenge, was now as easy as walking. As they reached the bathroom at the end of the hall, Mimi tenderly pushed Aly through the doorway and urged her to take a look in the mirror.

When Aly finally faced her reflection she, too, was taken aback at her appearance. Her right eye was a bit swollen from crying, but her left eye… was something else entirely.

“What the…” The words involuntarily slipped from Aly’s lips as she ran her fingers across the left side of her face. Her eye was red. But not just inflamed like the sclera in her right eye – _everything_ was red. Even the color in her iris that was once a chocolate brown was now a deep blood shade that reflected the liquid from the syringe.

_ So this is what Determination looks like. _

Not only was there the discoloration, but Aly winced as she began to touch a tear in her skin opening up from her bottom lid and stopping just short of her cheek. Dried blood sprinkled the area around it. Aly glanced back at Mimi, still standing pensively on the other side of the bathroom doorway. When she opened her mouth to say something, nothing came out.

“Aly,” Mimi started first.

Aly stood motionless, desperately searching inside to try and find an answer. 

“Please… just tell me what happened.”

“I-I…” Aly still couldn’t get any of the words to come out.

The waterworks were quick to begin. Frustrated, Mimi weakly shoved Aly deeper into the bathroom as she squeezed her way in and shut the door behind her. 

“Why wont you _talk_ to me?!” Mimi cried. “Why is this so hard?”

Aly stumbled backwards uneasily and caught herself on the door of the standing shower. Seeing her sister hurt by her actions (or lack thereof) made it impossible for Aly to conjure up any excuse to quell Mimi's emotions. She couldn't think; her mind was wrapped around the desire to desperately tell the truth, yet the fear of Gaster's words still resonated inside her.

“Mimi, I promise it’s nothing.”

“That’s bullshit!” Mimi shouted in between her sobs, hovering inches from Aly’s face. It had been a very long time since Aly had seen her sister this worked up. To be honest, she didn’t know how to handle it. It had all escalated so quickly. Or... maybe it hadn't. Aly always tried to protect her sister, even if that meant hiding the truth. Maybe Mimi had always been wise to that and this was just the breaking point. Either way, Aly could barely carry the weight of her secrets any longer.

“I just had to pull some strings to get the medicine, okay?” Aly finally retaliated. Regret immediately hit her though, unsure of how much information was too much. That, and the now guilt-ridden expression glued to Mimi's face didn't help matters either. 

“W-What…?” Mimi paused. Her eyes widened in shock. Aly knew Mimi was feeling ashamed of how she acted upon hearing her sister's sacrifice. This wasn't what she had intended at all. 

“But it looks like it was worth it.” She quickly pointed to Mimi’s leg, trying to make her feel better. The wound that, just two days prior, was grossly infected was now nothing more than a thin mark. Aly began to simultaneously laugh as she felt tears rolling down her own cheeks. “And you know what? I would do it over and over again if it meant seeing you like this – awake, healthy… _alive._ ”

Mimi relaxed her tense muscles as she wiped her current tears away, only for them to be immediately replaced with new ones. "Aly... Aly, why...?"

“Don’t you understand how terrified I was?” Aly continued. “How hopeless I felt watching you die as I sat around doing nothing to help? I-I was going to lose you, Mimi…” Her voice began to tremble as she averted her gaze away from her sister. “A-And then what was I supposed to do, huh? What would have been the purpose of continuing if I didn’t have you?”

The both of them began to weep even harder. Mimi finally wrapped her arms tightly around her sister, and Aly eventually returned it. 

“Aly…” was all Mimi could manage in between her cries. 

“Just… don’t scare me like that again. You’re not allowed to leave me alone.” Aly squeezed her arms tighter around Mimi. “You promised, remember?”

“T-To the ends of the earth…”

“And whatever lies beyond it.”

 ***

Aly and Mimi had quietly slipped into Sans’ bedroom after their exchange. Papyrus had left plates of spaghetti outside of the door before retiring to his own room for the night. Sans was understanding of the girls’ need for privacy as he made himself comfortable on the couch like he had been doing for the last couple of nights before Mimi woke up.

The girls sat on the bedroom floor for what must have been a couple of hours now, talking by the dim light of the lamp atop Sans' dresser. Mimi had spent a great deal of time gently reaching for more details about what Aly had endured for that medicine. But she knew her sister too well. The fortress Aly had created around her thoughts and emotions was strong... but not impenetrable.

At last, after a long stretch of cajoling, crying, and as much comfort as Mimi could manage, Aly couldn't hold it in anymore. The strong walls came crashing down.

She told Mimi everything.

Understandably, all of the information was overwhelming. Mimi couldn’t even gather the correct emotions to process everything Aly was throwing at her. Things about this mysterious monster named W.D. Gaster, and the Void, and...

Mimi looked down at the object Aly had handed her sometime during her recollection. A journal that supposedly belonged to their parents, though neither she nor Aly had even worked up the nerve to open it yet. But they couldn't avoid it forever - Mimi knew that. She looked to Aly for any sort of reassurance, and Aly nodded back at her.

Mimi opened the journal to the very first page, written in her father's barely legible handwriting. She read it aloud:  

> _ "Catherine and I arrived to the Underground one week ago with the rest of our team. The king, King Asgore, has been generous enough to see to it that we would have all the necessary accommodations to make our extended visit as comfortable as possible. Tomorrow, we’ll be meeting with His Majesty’s Royal Scientist and begin the preparations needed to get these citizens to the surface. It’s a very exciting time to be alive indeed. Cath and I can’t wait to compare research with the scientists of the Underground to see how differently our worlds have developed through centuries of separation. In that respect, it was very smart for King Asgore to call upon us and ensure monsters’ bodies are going to acclimate to the change in environment properly. The effects centuries of dwelling underground will have on a monster’s physical makeup are currently unknown. However, we have hope for a smooth transition within the next few months. I just hope our girls will understand." _

For such a small journal, it was packed with several entries. Mimi skimmed through most of them, stopping on the most poignant ones to read. Another entry nearing the middle of the journal caught her eye.  

> _ "The Underground has been quieter lately. Every month, we are able to send more monsters across the border. The ambassador for monsters visited the castle today and we were able to meet them. Their name was something peculiar. Frisk, I believe. A human child, couldn’t be much older than our own girls. From the way the king spoke, it seems they were somehow responsible for breaking the barrier. I would love to learn more about them in my time here, and that doesn't seem like it will be hard. They are a friend to all – and so very, very kind. In the brief time I spoke to Frisk, I could have sworn I was listening to my own daughter talk. Mimi is going to be just like her mother one day. And I hope Aly is helping her stay strong for me during these times." _

"Dad..." Mimi was struck with a sudden emotional closeness to a man that she had forgotten about for so long. She still couldn't remember what he looked like or how his voice sounded. But suddenly, it was like pieces of him were coming back to her.

Not only that, but the monster ambassador's name!  _Frisk._ How could Mimi not recognize it? Surely that meant their parents had met Sans and Papyrus too. She would be sure to ask them in the morning.

"You were always his favorite," Aly mused.

"...I was?" Mimi could still barely remember her father's personality beyond the words on the page. It seemed Aly was having a much easier time recalling these details.

Aly nodded, the faintest smile gracing her lips . "Naturally. You were the good twin."

Mimi returned the smile,"I doubt that, Aly. I think they loved us both equally..." She continued flipping through more of the journal. "They loved us very much..." A flood of warm emotions filled her as she began to remember a little more about these two strangers. However, it was short lived as she paused when she got to the last several pages in the back.

"What's the matter?" Aly asked, scooting closer to Mimi and craning her head down at the book.

"W-What is this...?" Mimi squinted her eyes as she continued to flip page by page. Each entry after this point was written in some sort of code. Symbols, like black ink splotches on the paper. There were miscellaneous symbols sprinkled in - flags, and faces, and crosses - but mostly crudely drawn hands gesturing different forms. She turned the journal to Aly. "Do you know?"

Aly silently scanned her eyes down the page, as if she were reading it perfectly fine. However, her answer begged to differ. "...I don't."

"I wonder if Sans would know—"

"I don't think we should bother him with this." Aly was quick to interject.

"Why? This is huge, Aly! And he could help us! I have a feeling he knew them and—"

Aly suddenly grabbed the journal from Mimi and closed it before scooting even closer so that they were now only inches apart.

"I said _no."_

Aly's raised voice stopped Mimi in her tracks. She understood that Aly had a lot weighing on her at this moment, but she couldn't understand the reason why this simple suggestion made her so defensive. There was an air of awkward silence between them as Mimi averted her eyes away in embarrassed defeat.

“Okay, then… what are we going to do now?” Mimi asked apprehensively, trying to steer their conversation back on track. “I’m not going to let you go back to Gaster for him to finish...” She grimaced at Aly's eye. “Whatever _this_ is.”

Aly’s expression wavered. “I don’t know if that’s a choice I have anymore, Mimi.”

“Of course it is!” Mimi assured her. “Sans and Papyrus will keep us safe.”

"Stop mentioning them," Aly snapped, rubbing her temple with her fingers. “It’s not that simple.”

Mimi did her best to keep her hurt feelings in check, reminding herself over and over that Aly didn't mean it. “Then... what can we do?”

“Leave."

The suggestion made Mimi hesitate. Leaving was inevitable, but it never occurred to her that it would be happening so soon. But then again, she had lost track of time since developing her fever. How long had it really been since she and Aly fell down the mountain? A few weeks? Maybe a month?

Regardless, they had overstayed their welcome. And for Aly’s sake, this was the right thing to do. There was no telling what would happen if they waited to see what Gaster’s next move would be.

After a moment of thought, Mimi nodded solemnly. “I guess you’re right. The trip will be a piece of cake now that I can walk again. We can take tomorrow to prepare—"

"Tonight," Aly interrupted. "If we're going to leave, we have to leave immediately."

"Aly, it's the middle of the night! We're not going to get very far in the dark - especially on our own."

Aly grimaced, knowing Mimi was right.

Mimi could see the desperation in Aly's face, looking for any way out to avoid going back to the Void. Mimi was  _terrified_ for her sister. And this whole experience had put Aly in a rare form; unable to control her emotions or think logically.

“Tomorrow,” Mimi rested her hand on Aly’s leg to comfort her. “Please, just take the rest of the night to get some sleep and regain your strength."

Aly's pupil's shrunk in fear. "I can't."

"Please, sis," Mimi pleaded. "I'm going to be here right beside you the entire time. You were there for me. Let me protect _you_ this time."  


Aly hesitated, clearly trying to assess the options in her head. Mimi didn't want to give her the chance to think about it too hard and quickly scooped her sister in her arms and held her as tightly as she could once again. "Please, Aly..." she begged even more.

Finally, she felt Aly's tense muscles relax under her grasp. "Alright... I trust you."

Mimi let out a sigh of relief as she released Aly. "It'll give us time to say goodbye too..." She tried to force a smile, but the more she thought of Sans, the harder it was to keep it on her face. It had been so long since she felt this way about anyone, and with as much as she and Aly traveled, there was no real guarantee of when they would see the brothers again once they were back on the Surface. However, when given the choice, she would always choose her sister over anyone and anything else.

"No goodbyes," Aly mumbled.

"Wait, what...?"

"Mimi... I wasn't supposed to tell  _anyone_ about this - not even you. So please... don't make this harder than it has to be to leave."

Mimi stared into her sister's eyes for a long time after that. Aly's left eye was still a jarring sight, bloodshot and scarred from the unimaginable pain she had to endure. The right... was full of fear. Scared, and anxious, and frantic - all emotions she really wasn't used to seeing come from her twin. And just as if they were connected, it made Mimi feel the same things. She would comply with anything Aly said as long as it kept them both safe, even if that meant disappearing from this world. Because, at last, they were in this together again. And together, they could overcome anything.

It hurt, but she trusted her sister with every fiber of her being. "...Okay then. Tomorrow."

They would quietly slip out and leave the Underground tomorrow.


	12. The Experiment

**Summary for the Chapter:**

> Gaster's experiment continues.
> 
> **WARNING: This chapter contains body horror, medical trauma, and mentions of suicide/death.**

**Notes for the Chapter:**

> We're finally here at the climax of Undertaken! This was the longest, most challenging chapter yet. Huge thank you to [Admin Sans](http://adminsans.tumblr.com/) of [The Undertale Fandom](https://www.facebook.com/theundertalefandompage/?fref=ts) Facebook page for being our Beta on this one because it required much more work than just the two of us could handle. Also thanks for 640+ hits, which is INSANE considering we were at less than half of that during the last chapter's release. It's going to be an intense ride from here on out, so we hope you guys enjoy it!
> 
> Also lots of new art on our [Tumblr](http://anundertaleoftwosisters.tumblr.com/)!

With the promise that Mimi would keep her safe through the night, Aly fell hard into her sleep. Her string of lucid dreams combined with Gaster's parting words had made her fearful that she would face something unpleasant tonight. However, this wasn't the case at all.

Aly was standing in a familiar living room, the tired wooden planks underneath her creaked each time she shifted her weight. Everything was exactly as she'd remembered it from her childhood. The family sized sofa against the wall. The grand piano tucked tightly in the corner. The french doors leading out to her mother's flourishing garden.

The only difference were the picture frames on the fireplace mantle. Aly hadn't remembered even seeing them there in real life - not for a very long time, anyway. And instead of being filled with photos, they were all blank.

"My dearest Alyson," a gentle male voice called from behind her. It took Aly a moment to process it, nearly forgetting that it was calling  _ her _ name - a name so unfamiliar to her now after going for so long without hearing it.

There were only two people to ever call her that. Aly slowly turned around. "...Dad?"

The man addressing her was leaning against the doorway on one shoulder. His jet black hair was peppered with gray and matched the dark sweater and slacks he was wearing. The wrinkles and lines in his face creased as he smiled at her. Everything was as she remembered, down to every last detail of his skin.

"Welcome home, my love."

_ Home. _ Aly was home, and yet she knew that she wasn't really. But... maybe just pretending for a moment wouldn't hurt. She desperately missed this feeling, even if she knew it couldn't last forever.

"Why am I here?" Aly scanned around the room, recalling more details about it as she looked closer; a clock on the wall that was stopped on the incorrect time. The decorative area rug. The vase of golden flowers on the coffee table. "I-Is mom here too...?"

"You know your mother, always tending to that garden," her father chuckled as he gestured at the french doors on the furthest wall. "You're here because this is where you belong - you and Mimi both.  _ With us." _

"Then... why didn't  _ you _ come home?"

Her father's expression dropped. "I'm afraid... there just wasn't enough time." He paused, knowing it wasn't a sufficient answer for Aly's mind, just as sharp as his. So he continued, "Not enough time to learn everything there was to learn, or save everyone that needed saving. And there would certainly never be enough time to spend with you girls, even in one thousand lifetimes."

"That's a lie." Aly gritted her teeth. "We waited. And waited. And waited. Eventually, the letters stopped coming. And then... everything about your existence just... disappeared." She was still perplexed about that part.

"The doctor thought... it would be better that way," he tried to justify. "That maybe, just maybe, it would hurt you and your sister less to just forget about us altogether."

"Don't mention  _ him. _ Not after what he did," Aly snapped. "Because, for the record, it  _ didn't _ hurt less. After the nanny died, we left everything and spent our whole lives going on a wild goose chase for you." She was shaking now. She didn't want the first 'conversation' with her father in all these years to be like this, but he had to know the truth about how hard she and Mimi fought for them. "And for what? To find out that... that...  _ thing _ murdered you?"

"He was our friend, Aly. And he was extremely taken with you girls."

"I  _ saw _ what happened to you!" Aly cried out, no longer able to contain her heartache. The tears shortly followed as she reached for her next sentence. "Now you're gone and the only way I can even argue with you is through these stupid dreams."

Before Aly could see beyond her watery eyes again, she felt the gentle  _ thud _ of being pulled in against her father's chest.

"Are you afraid, my dear?" he whispered softly. "Is that what it is?"

"Of course I'm afraid... I'm scared out of my mind." Aly's voice was still quivering as her reply was muffled against the fabric of his sweater. "That can't happen to me, not when I have to keep Mimi safe."

His embrace was intoxicatingly warm. It made her crumble. All the growing up she had to do, all the strength she had to wear on a daily basis for both her and Mimi's sake... none of that meant anything now. Suddenly, she was ten years old again. She lived with her parents and her sister in this beautiful house where love was enough to sustain them.

And she loved her father so very much.

"I promise you, Aly. You will be alright," he assured her, pulling her closer. "I am so proud of the beautiful woman you have grown up to be. You have your mother's grace and more determination than even I had."

"Don't make me go back, dad," Aly wept. Suddenly, the pull back to reality was getting stronger. This was the end, as much as Aly would have given up to just stay here like this forever.

"You have to, darling. You’re the only one that can finish what your mother and I started.”

Aly was hurt that just staying together like this wasn’t enough for him. “...Is this really what you want me to do?”

“Do you trust me?"

"O-Of course..."

"Then we'll go together."

"Together...?"

"You will never be alone." Her father released her from his embrace and grabbed her hand, pulling her towards the doors leading outside.

Aly could no longer make any words come out beyond her crying. She simply let herself be pulled. She would follow him anywhere if it meant this feeling could remain with her.

"I love you, my dearest Alyson."

His voice was getting further away from her. Aly could feel her heart breaking from inside her chest; falling apart into a million pieces and disappearing with her father.

"Stay determined."

***

Mimi wasn't sure what that feeling in her chest was that woke her up, just that it did. It was a lingering throb in her heart, like something was pulling it right out of her body.

She jolted up from Sans' bed, keenly aware of the empty space beside her and the biting air coming from the open window above her.

_ No. _

She scrambled out from under the sheets and to her feet as she scanned around the room for her sister in the dark, regardless of how futile the action was.

_ No no no no no no. _

Mimi ran to the window and dangled her entire upper body from it, looking two stories down at the ground. The footsteps in the snow were still freshly imprinted and had yet to be covered again by a new layer of white.

_ She couldn't have. _

Aly jumped. How the hell did she  _ jump _ ? Was she alright after hitting the ground? 

...How was Mimi supposed to do the same?

_ I have to tell Sa—  _ Her own thought was interrupted by another. She couldn't tell Sans - she promised Aly that she wouldn't.

She had to do this alone, and she had to act now.

But she was  _ not _ going to jump out that window. She knew she was incapable of doing so.

Mimi quickly grabbed her jacket from atop the dresser, zipped it up, and flipped the hood over her head. She slipped on her shoes at the bedroom door before opening it as slowly as possible. Luckily, the hinges made no creaks as she slid through the opening and gently shut it behind her. 

The living room beyond the staircase was pitch black. Silently moving down the stairs, Mimi squinted in the darkness to see the silhouette of a small mound on the couch - Sans, unmoving and seemingly fast asleep.

_ All I have to do is make it through the front door. _ Mimi's stealthiness was costing her more time than she had to spare to catch up to Aly. She slowly tiptoed past the still skeleton with his back turned to her, face buried into the backrest of the sofa and the slightest snore emitting from him through quiet breaths.

To her relief, he didn't stir when she arrived at the door, or even when she turned the knob and it creaked open, letting in the tiniest shred of outside light into the entryway.

Once Mimi successfully made it to the other side of the door, she booked it. Aly's light footsteps were still sprinkled in the snow, so she ran as fast as she could to keep up with them before they disappeared. They were leading her to the outskirts of town.

"What is she  _ thinking _ ?!" Mimi panted. It wasn't like Aly to do this. Leave, maybe. But not under these circumstances. Not after their conversation and Mimi's promise to protect her while they planned their quiet exit together.

Aly's tracks continued, but this was now all new territory to Mimi. The snow had ceased to fall here, making the sheets on the ground thinner as well. The footsteps were fainter here, making her progressively more worried.

All of her fears came to fruition when the snowy path stopped abruptly. The cavern ahead was dark - too dark for her to continue any further without a light.

Against her best judgement, Mimi continued anyway. She had no choice.

But she was moving blindly now. The sound of running water filled the dark caves and she wished it hadn't because she had lost any chance at listening out for her sister if she was close enough.

“Aly!" Mimi began to loudly whisper over the roar of the water. She kept both hands up in front of her, feeling for walls and adjusting her path accordingly. Every few steps she would call again, gaining more volume as she headed deeper in. The stones began to gleam against the cave's moisture, lambent flora lit the walkways. It was now easier for Mimi to see, but that didn't make her any less lost.

Her legs were on fire. She was out of breath. She could barely see a foot in front of her, and certainly couldn't think. And no matter how many times she called out for her sister, she knew she was no closer to receiving an answer.

The walkways began to split more and more as she continued. One path turned into several, which turned into several more. It was a maze she wasn't prepared for, crossed with an infinite amount of bridges and waterways.

"Aly..." Mimi cried out a few more times, on the verge of tears as her pace slowed across one of the bridges.

"W-Why...Why would you do this, sis...?"

It made no sense. There was no reason Aly would go off on her own under these circumstances.

Unless she was being forced to.

Mimi staggered against the damp wooden planks and eventually came to a stop. How was she supposed to do this on her own? The constant self-doubt was beginning to overshadow her determination to find Aly. It was a weight on her heart, pushing down harder and harder the more she let the feeling of hopelessness take hold.

Suddenly, the weight stopped pushing down. Instead, it pulled her. The same sensation that woke her up.

It was Aly.

Her sister's shadow coasted along the cavern walls in the light of the glowing waterfalls, just a few yards ahead.

It was an insane stroke of luck, but Mimi was going to hold onto that and run with it... literally.

At the first sight of Aly's presence, Mimi sprinted from the bridge, nearly slipping on the puddles of water splashed up from the canals. She followed the faint silhouette of her sister's figure hugging one of the northern walls in particular. At one point, she was so focused on keeping an eye on that shadow that she lost her footing and half of her lower body dipped into one of the banks, soaking her leg and the bottom of her dress. The water was alarmingly cold, most likely from its proximity to Snowdin, and sent an aching chill all the way up her body. Mimi yelped at the sensation, but shook it off and remained steadfast.

Finally, her sister came into full view. Aly dragged her feet as she languidly drifted through the shadows. Her steps seemed listless, mechanical - like she wasn’t moving on her own accord.

“Aly!” Mimi yelled across the water as loud as she could. However, Aly did not respond or acknowledge her at all.

“Aly, stop!” she called again when Aly turned a corner and briefly disappeared from her view. However, it only took a moment for Mimi to finally catch up and turn the corner as well.

What awaited on the other side was… unexpected. A hidden corridor tucked behind the cave walls, one Mimi would have never found on her own.

And a door.

As Aly approached the peculiar entryway, Mimi grabbed her sister’s arm from behind and pulled her to a halt.

“What do you think you’re doing out here?!”

Mimi could feel Aly’s muscles tensing under her grip, but her sister didn’t answer or otherwise respond to her presence.

Instead, Aly began to jerk forward, pulling Mimi with her as she continued towards the door. And Aly was strong, much stronger than she was. Mimi had no hope of stopping her with physical force.

“Sis, tell me what’s going on!” Mimi pleaded, stumbling over the slippery ground as she held on tight to Aly’s arm.

Aly reached for the door’s handle with her opposite hand, still ignorant of Mimi’s attempts to stop her.

This was bad. This wasn’t Aly at all. And whatever was behind that door…

Mimi had to stop her.

Instead of trying to pull her sister back, Mimi veered around and wedged her body in between Aly and the door. Their faces were inches away from each other now, allowing Mimi to notice her sister’s state.

Aly’s eyes were barely open, glazed over by sleep or… something else.

This was Gaster. It had to be.

Mimi grabbed Aly’s shoulders and shook her frantically, trying to wake her up. “Aly, listen to me,” she shouted. “Listen to my voice and  _ wake up. _ ”

It became apparent that Aly’s mind was actually resting somewhere in between dormancy and cognizance, because she  _ did _ react to Mimi. As Mimi shook her, Aly grabbed one of Mimi’s wrist and clutched it so hard that her own hand began to tremble.

Mimi shrieked in pain and attempted to jerk her wrist out of Aly’s grip. “A-Aly… s-stop…!”

Aly remained detached, glossy eyes devoid of any conscious feeling. 

The bones in Mimi’s wrist began to pop and crack under the pressure. She screamed as she tried to push Aly away with her free hand.

...That was a bad idea too. Before Mimi could react, Aly had shoved the hand away and used her own to grab Mimi’s neck.

_ This isn’t my sister,  _ Mimi was having trouble reminding herself as she choked for air. She could feel Aly’s fingers wrapping tighter all the way around her throat.

“A-A-ly-y…” 

Mimi’s entire body shook violently as she struggled to break free. And with every movement, Aly’s grip stiffened.

_ I’m… I’m going to die here. _

Mimi’s heart was pounding slowly in her ears as she listened to the life slipping from her body. Aly’s absent expression was the last thing she caught before her vision blurred too much to see anything at all.

_ It’s not you.  _ Mimi wished she could somehow try to tell Aly that one last time. But there was no time left before everything faded to black.

 

It only felt like a second in the dark before a light drew Mimi back out.

With one heavy inhale, life cycled back through her once again. Mimi’s body jolted up from the damp ground as her eyes shot open.

“Kid!”

Sans was crouched next to her, beads of sweat trickling down the side of his skull. “Oh, thank god.”

“Sans…?” Mimi croaked, her throat still sore. She glanced over and noticed Papyrus standing behind Sans as well. She was still in the same corridor as before, but the brothers had somehow managed to locate her regardless. “How... how did you find me?”

“If you were going for stealth, maybe don't walk through the front door next time,” he chuckled softly.

“What happened to you, Mimi?” Papyrus asked frantically.

It only took a moment for the previous occurrence to push its way to the front of her mind again.

“The door!” Mimi clambered to her feet, stumbling slightly when she put weight on her wrist that she just remembered was injured now.

“Kid, what—”

Mimi wildly shifted her view to each wall, searching for the door. But she remembered it’s location so clearly. After all, she had  _ just _ seen it.

_ It should be right here.  _ She touched the wall closest to her.

But it wasn’t.

“T-This can’t be right…”

“Mimi, what is it?” Sans called out from behind her. “How did you end up all the way here in the middle of the night?”

“It was  _ right here _ …!”

“Mimi, where’s Aly…?” Papyrus chimed in.

Mimi was barely listening to either of them. Her mind was completely wrapped around the door. She didn’t imagine it.

It was _ there _ .

“Let’s get you back home, kid.” Sans tried to pull her away from the wall.

“N-No!” Mimi shoved him away and began to strike the rocky surface with her fist. “I need to save Aly!”

“Mimi!” Papyrus used his size over her to grab her arms and stop her from attacking the wall any further. Just a few strikes to it had cut the skin on her knuckles open, bloody and raw. “What are you doing?!”

Mimi was hysterical now, sobbing and gasping for air as she cried out for her sister. She wasn’t crazy. She followed Aly all the way here. There was a door, and now there wasn’t.

“Gaster!” she wailed, knowing there was no point in hiding what she knew anymore. “He has her!”

Time stood still for a moment as the air between the three of them thickened.

Sans was the first one to speak, but his voice had quieted to a trembling whisper. “...What did you say?”

“T-There was a door,” Mimi tried to resume explaining through her uncontrollable tears. “She… she wasn’t herself! Gaster was doing something, c-controlling her somehow and—”

“That’s  _ impossible. _ ”

“Aly told me! Sh-She wanted us to leave tomorrow without telling anyone because she was so afraid of him…”

The brothers glanced at each other with a silent understanding that Mimi was left out of.

Papyrus’ hold on Mimi loosened. “Sans…?”

Sans nodded at him. “Find her, Paps. Any trace of her whatsoever. I'll take the kid home.”

“What?! No!” Mimi protested. “We’re running out of time! Let me help—”

“You've been through enough.” Sans grabbed Mimi’s hand and delicately pulled her away as Papyrus wasted no time heading in the opposite direction to further examine the area. All the while, she sobbed. She felt so helpless.

Aly was right there in front of her. Mimi had the chance to save her…

And yet she didn't have the strength to.

After walking for a few steps, she crumbled under the guilt.

“Mimi!” Sans caught her in his arms before she fell to her knees.

“I… I couldn’t save her…” she said between trembling sobs.

“It’s not your fault—”

“I promised her I would protect her, Sans!” Mimi gripped his sleeves and cried into the fur of his hood. “She trusted me and I let her down!”

Sans pulled away slightly and stared deep into Mimi’s watery eyes. “Listen to me, kid. I  _ know. _ I know about Gaster, and I know that’s where your sister’s been running off to. I just…” he wavered, his voice barely a murmur. “I just didn’t think she would go back after the last time. I thought you girls were safe.”

“It wasn’t her,” Mimi insisted, gingerly touching her aching neck. “Aly would never hurt me like that…”

“He’s found a way into her head,” Sans explained. “Her nightmares, her insomnia… his grip on her has probably been building for a while.”

“We have to do something!”

“We will, kid. But we’re, uh, runnin’ on fumes here. We’ve got no idea how to find them.”

“There was a door,” Mimi felt like she had repeated that for the millionth time. “A hidden door in that corridor. But I was knocked unconscious before I could stop Aly from going in.”

Sans rubbed his temples, as if trying to visualize it from deep in the back of his mind. “...I don’t remember a door.”

“What about Papyrus?”

“Paps knows as much as I’ve told him. I’d like to keep it that way.”

“Then it’s hopeless…”

Sans rested Mimi’s hands on his shoulders and helped push her back to her feet. “You’re starting to sound like me, kid. Not a good look for you.”

Mimi had trouble standing. Her entire body was so weak and her head was spinning.

“What’s going to happen to her…?”

“...I don’t have the answer to that.”

Mimi wished Sans would just tell her that her sister was going to be alright. Though she had a feeling that he knew much more than he was letting on - that always seemed to be the case.

But for the first time, Mimi was grateful that he was sparing her feelings. She was barely holding it together right now, trying to lie to herself that her mistakes wouldn’t cause Aly any harm.

She was never a good liar.

***

_ Please don't make me wake up. _

As hard as she tried, Aly could no longer call back the dream. As hard as she searched, she could no longer find her father. The bliss of his ubiquity was beginning to wear off as reality was taking over Aly's conscience once again.

It was... painful.

...Not just in the figurative sense, either. As Aly became more aware of her physical presence, she realized that she was actually hurting. She felt her limbs pushing against some sort of resistance. And each time she tensed her muscles, the veins in her arms, wrists, and hands pinched with a stinging sensation.

Suddenly, she was acutely aware of the cold, steely surface she was lying on - a far cry from the warm bed she had fallen asleep in next to her sister.

_ No. _

"Still dreaming," Aly tried to reassure herself through calming exhales, afraid to open her eyes. "I'm still in Snowdin. I'm still in Snowdin with Papyrus, and Sans, and Mimi..."

A broken voice jaggedly cut through the air, almost mockingly.  _ That _ voice. The confirmation that she had returned.

When Aly finally gathered the courage to open her eyes, she was met with a dim red glow surrounding her face from all sides. There was a machine looming over her head that she could not fully see, emitting this light from its gaping core like the mouth of a beast about to devour her. As she glanced up, silhouettes of hundreds of tubes and wires attached to the machine dangled loosely from the ceiling. In its light she could also assess the rest of her body, lying stiffly on the operating table.

Her limbs were secured to the edges of the table by thick straps. Her long-sleeved shirt had been removed, leaving her with just a sleeveless undershirt tucked into her skirt against the biting cold of the Void. With her limbs exposed, she could clearly see needles affixed to long tubes embedded in each of her veins from the creases in her arms down to the tops of her hands. The sight alone was making Aly's weak stomach nauseous.

Panic was setting in as she grasped more of the situation. 

"Gaster..." Aly managed to whisper under her shaking breath.

Suddenly, a set of hands appeared in the dim glow of the red light. They signed swiftly in tandem with Gaster's stern voice that was everywhere and nowhere all at once. "I believe we had a deal, remember?"

"Not... like... this..." Aly heaved as she fought against the restraints. The needles throbbed as they jostled underneath the surface of her skin, biting painfully every time her veins pulsated.

The rest of the doctor's unnerving figure finally appeared next to Aly. He gazed down at her from his dark, melting sockets while wearing just the faintest glimpse of that harrowing grin.

"I would refrain from doing that if I were you."

Aly didn't want to stop. She wanted to fight him with every fiber of her being, regardless of how futile it was. However, her body couldn't keep up with the demands of her mind. The pain anchored in her arms was becoming too much.

She wasn't going to escape. Maybe she had always known that, but was never quite ready to give up.

Although her breathing was still heavy, Aly sat still for a moment before finally looking up at Gaster.

"How...?" she barely breathed through her teeth. How did she end up back here so easily?

"You walked right through that door, darling," Gaster mused. "You seem to have been... sleepwalking."

It suddenly hit Aly like a speeding train. The dream. Seeing her father again. Speaking to him, feeling his presence. 

All a lie.

"I-It... was...  _ you _ ..."

Gaster continued to stare at her, pitiless and silent.

The cruelty of it was insufferable. Aly couldn't fathom how Gaster already had this level of control over her conscience, even before consenting to his tests. And he knew,  _ he knew _ , exactly how to lure her back. The promise of retrieving something so unattainable...

Aly didn't realize she could despise Gaster anymore than she already did. Her heart was splintering under the weight of the betrayal.

"It was you," she repeated, trying to let it sink in past the fading comfort she had felt in her dreams. And as much as she wanted to cry, she couldn't call any tears beyond the anger. Aly pushed the image of her father into the back of her mind. He wasn't the one that she spoke with. He wasn't the one that reminded her that she was loved.

"It was you."

How cruel.

"You left me no choice." Gaster's austere tone was detached and most likely unsympathetic of Aly's anguish. "I'm afraid you haven't been holding up your end of our agreement very well."

"Does it matter anymore?" Aly almost wanted to laugh at the hopelessness of her situation. And it  _ was _ funny, how hard she was willing to try to avoid this and how hard she had failed.

"Your sister knowing what she knows now... complicates things."

Aly perked her head up as high as she could off of the table when Mimi was mentioned. The rest of her body instinctively pushed against the straps and needles again. 

Gaster disappeared from her peripheral vision and began to switch on the machine above her, evident from the rumbling hum as it came to life. His hands remained to continue speaking for him, "I'm truly disappointed that you couldn't keep this our little secret."

"P-Please..." Aly stuttered, unable to think of anything else to say beyond the dismay of remembering Mimi. "Just... leave her out of this."

"Don't worry, my dear." Gaster came back around to Aly's side. "I have no interest in harming your sister. But she knows of this place's existence now. She followed you to the door and  _ will  _ return find you. We can't have that."

_ Mimi... followed me?  _ Aly was trying so hard to remember the events that led her back here. Unfortunately, none of it was coming back to her. Gaster had orchestrated her return entirely on his own and some unknown force kept Aly unwillingly bound to his demands -  _ especially _ in her sleep.

"What does that mean...?" Aly drew her focus back to Mimi. Everything she ever did was for  _ her. _ And for Mimi to get involved in all of this…

"It simply means we must expedite the process." Gaster ran one of his hands across the exterior of the machine as it hummed and groaned. "This machine was once created for extracting Determination from a human soul. However, after your parents transported it here from the Royal Scientist's laboratory, they were also successful in reversing it."

He ran another hand along one of the long tubes attached to Aly's arm. The movement startled her as the needle shook. "Instead, the human soul now acts as a conduit, channeling that trait into the machine and allowing it to be output back to its host, twofold."

Aly could feel the palpitations of her heart hammering in her chest faster and heavier. "W-What kind of soul could even handle that kind of strain on it...?"

"The injection earlier was a test," Gaster replied, bringing attention to her left eye, still reddened and devoid of sight. "To see how well your soul specifically would react to the additional DT. As I said before, the results weren't as strong as I'd hoped. The idea here was to use this machine to steadily increase the dosage as your body acclimated but..." He leaned in closer now, that thin grin more unsettling than before, as if he were actually quite amused now.

"With your sister aware of your whereabouts, it appears we no longer have that luxury."

With the click of one more switch, the needles began to vibrate under Aly's skin. She shifted her eyes from side to side, trying to figure out what was happening. Suddenly, she could feel a familiar tugging in her chest. Her soul was being ripped from her body, exposed over her chest and fighting against the pull of the machine. It was an unpleasant sensation under a veil of anxious desperation as if the soul was being stolen from her. Aly still wasn't used to the magic that coaxed such an integral part of her out so effortlessly. In a way, seeing her soul separate from her body felt... violating. She felt robbed, and all she wanted was to reach up and bring it back.

After a few minutes, red liquid began to trickle through the tubes and slowly make their way closer to Aly's veins. Instinctively, she tried to fruitlessly shake it away as her fists wriggled and stirred beneath the binds. 

"I-Is this going to feel like before...?" Aly asked apprehensively as the liquid made its way down from the machine.

"Not quite." Gaster's hands paused as he watched the bright red substance finally hit contact with her veins.

Three. 

Two. 

One.

The effects hit just as rapidly as before. But this time, it was coming from every direction - twice as hard.

Aly's muscles involuntarily locked up, the restraints cutting deep into her skin. She opened her mouth to scream, yet nothing came out. Even if she could speak at all, there were no words to describe the sensation that shot through her entire body in that moment. 

She could hear her heart pounding in her ears, frantic and harsh. Her soul, still visibly hovering above her, mimicked the same beat - struggling to feed the machine incessantly draining it of Determination only to siphon it back into Aly's veins with double the potency. 

The pain was like nothing she had ever experienced, making the injection from before feel insignificant.

Aly could feel every single time another drop made its way out of the needle and breached her bloodstream. Her heightened sense of feeling was an unwelcomed side effect. It was acid in her blood, eating away at her insides and corroding her bones. She couldn't move, she couldn't breathe, she couldn't get her body to do anything beyond the unimaginable pain.

Meanwhile, Gaster looked on. Unflinching and only looking down occasionally to check the tubes before resuming to watch Aly's suffering.

She shot him a wide-eyed look of hysteria mixed with unbridled rage.

His expression was so unreadable, impassive. If he had even the smallest amount of concern for her well-being, he certainly wasn't going to show it.

However, he did humor her with a listless explanation. "You have been unaware of your soul's capabilities, but this is going to jump start it. And before long, you're going to experience power you cannot even imagine."

"H-Ho-ow... l-long-g..." Aly managed to choke out beyond ribs that felt like they were caving in. Her body couldn't hold out for much longer. This was going to kill her before Gaster could continue.

"This is just the beginning, darling."

"I c-ca-an't..."

"But you  _ will. _ "

Aly focused on her heartbeat again - anything to keep her attention off the pain. She counted each beat as it sped by, starting again each time she would reach ten.

_ Not like this. _

She finally began to gather herself beside the pain. Every time she caught a glimpse of her struggling soul quaking under the roaring machinery, she could almost feel herself disappearing. It was like a slow and agonizing death that never came.

_ Not without a fight. _

Aly could feel the needles slipping from deep within her veins as she pushed harder and harder against the restraints. Even Gaster stopped for a moment to witness what was happening. Her soul was glowing even brighter in between its heavy, labored beats. Aly focused all of her energy on moving - on fighting.

“G-Gaster…” she hissed through her teeth as she gritted down on them. “S-Stop—“

“Very interesting indeed.” Gaster was pleased. “Your Determination is stronger than I thought."

Without warning, Gaster lifted one of his hands and waved it over Aly’s hovering soul. His fingertips sparked blue for a split second and, suddenly, the color of Aly’s soul reflected it. Her inherently red soul was now blue.

His voice had turned harsh. “But so is mine.”

Aly's entire body went limp, as if gravity alone were pinning down every muscle. Another type of magic that she had never experienced before.

“W-What is this?!”

“I’m surprised those brothers that you and your sister associate with have never showed you,” Gaster piqued as he gingerly pushed every needle back into place, unfazed by Aly's disapproving cries. “I swore Papyrus would have been overjoyed to show you his  _ blue attack. _ ”

“T-They’ve got no reason to attack us,” Aly spat out quickly in between focusing everything now to stifle back her screams once again. “W-We're friends!"

The phrase stopped Gaster for a moment, but then he continued to adjust the tubes without so much as looking at her. “Yes, that’s right. Friends.”

She was starting to lose focus, starting to slip. The liquid was toxic, poisoning every artery, every organ, and working its way to her core to infect her soul with a foreign version of itself. Sweat poured off of her skin, drenching her clothes and puddling onto the steel table underneath her.

_ Stop beating,  _ Aly tried to will herself. She had reached her limit, her body involuntarily convulsing and contorting against the weight of Gaster's magic. She was dying, and Gaster didn't seem to care.

_ Stop beating. _ She thought about her sister, but she couldn't focus for too long before the pain overcame everything again. Enough was enough.

_ Just... _

_ Stop. _

*** 

The days passed by agonizingly slow, leaving Mimi to believe the worst had happened.

"He won't kill her," Sans reminded her through the day. It was his attempt to be reassuring, but it never made her feel better. Did that mean Aly was suffering? Did it mean that, for every minute that they couldn't find her, she was being put through something worse than being killed?

Mimi couldn't stop crying at the idea. Every time she thought she was out of tears, more would find its way up. This was her fault. She made a promise that she couldn't keep, and now her sister was paying the price.

Papyrus had requested help from the Surface, but the Royal Guard had been grossly understaffed from years of never actually needing their services. After all, their king was no longer a king on the outside. He had taken off that crown years ago and allowed himself and his people to be emigrated into human society. Papyrus admitted that his title as Captain was arbitrary - only relevant in the months that he and Sans came back to the Underground.

However, the former Royal Scientist, Dr. Alphys, had agreed to make the trip down at Sans' request. Mimi was unclear as to how her presence would help them find Aly, but she wasn't about to question it or complain. She was in no position to do anything but leave it in their hands. Any help was better than none at all.

But there were too many plans. Too many ideas. None of which brought her any closer to finding her sister.

Mimi spent most of her hours lying helplessly on Sans' bed with her face buried in one of the pillows. Losing Aly to Gaster had made her forget a number of things; how to eat, how to sleep, how to do anything other than cry and blame herself.

Mimi didn't even notice Sans walk in and sit down beside her until she felt his fingers graze the skin on her arm.

"Hungry at all, kid?"

Mimi shook her head, not lifting her face from the pillow.

“‘Course you are, it’s been four days and you haven’t left this room.”

Had it  _ only  _ been four days? It seemed much longer. It felt like it had been months since she saw Aly for the last time. But maybe Sans was right - maybe it was just the hunger talking. However, doing any normal function made Mimi feel… guilty. She shouldn’t have been allowed to live a normal life as long as Aly was gone. After all, there was no way her sister was having any better of a time wherever she was.

Sans let out a large, defeated sigh. "Do you... want to talk about it?"

Another muffled head shake. As much as she reveled in talking to Sans, there was nothing left to say.

"Just tell me what you need from me, kid.” He hesitantly ran two of his fingers through Mimi’s unbrushed hair. She could feel his reluctance as he tried to find the balance between being comforting and getting too close. "...I hate seeing you like this."

Mimi lifted her head up just enough to whisper, "I need Aly..."

"Look, Paps is trying his hardest. He's out there looking every single day and night."

She was thankful for Papyrus too. He worried about Aly just as fervently as she did, even if he refused to show it. After all, he was The Great Papyrus, coolest Captain of the Royal Guard - dedicated to the job and to her sister’s safety. There was no room for weakness in his tall bones.

So Mimi cried enough for the both of them. In fact, more tears were already beginning to form at the edges of her eyes.

"...This is... all my fault..."

"Stop saying that." Sans snapped back quickly. She  _ had _ been saying it non-stop since that night.

"But I told her I would—"

Suddenly, Mimi felt Sans’ boney hands scoop underneath her enough to flip her over so that she was no longer attempting to suffocate herself in his pillow. He kept his hands tightly on her arms, forcing her to face him as he hovered over her.

"Look, if Gaster wants something, he gets it." Not the most comforting line to come from a skeleton that proved to not be very good at comforting in general. But Sans was trying. He tried relentlessly, saying anything and everything he could to try and make Mimi feel the slightest bit better. It wasn’t his fault that none of the words seemed to reach.

He continued his thought, "...And that's not something any of us could have helped - not you, and especially not Aly."

Alright, that  _ really  _ didn’t make Mimi feel better. "...H-How exactly do you know all of this...?" She hadn’t really brought up Gaster with him since the first time. Sans was too busy helping with the search and she was too busy wallowing in self-deprecation.

Sans’ expression wavered, a thousand words already spoken in his reluctant silence.

He released her and sat back down at the very edge of the bed again. “I didn’t want to say anything while Papyrus was around.”

Mimi wiped her tears away on her sleeve and sat up to give Sans her attention. Despite all the things Aly had told her, or how many times she reread the parts of her parents’ journal that she could understand, Mimi still had very little idea of who Gaster was or what he wanted.

“...I know because I’ve been in Aly’s place before.”

“But what… what does that mean?”

Sans was searching for his words again, delicately tiptoeing around the conversation. Hiding things to protect her, to put it simply.

Mimi frowned. Now was not the time for that. “Tell me everything, Sans. I need to know everything about what’s happening to my sister...”

“It’s… been a long time. But you don’t just…  _ forget  _ some of the things he’s done.” Sans paused, scratching his skull with uncertainty on how to continue. “He doesn’t care about anyone or anything above his research. Obsesses over it until it becomes reality. Hurts people, if that’s what it means to reach his goal.”

“...Did he hurt you?”

“Kid, I don’t think that’s—”

“Sans,  _ please _ ,” she begged.

Sans dragged a hand down his face nervously. Eventually, he gave Mimi a single nod.  “...Over and over again. Different ways, different experiments. Most of which I don’t remember anymore. But, like I said, some of them are harder to forget.”

Mimi’s eyes widened in horror. “What does this mean for Aly?”

Mimi could tell in the way his face pinched and contorted that Sans was having such a hard time trying to spare her feelings. “I… I don't know, kid. I honestly don’t. But your sister is strong, inside and out. She's probably giving the doc a run for his money... So trust me when I say that she's going to survive it." 

It was true. Aly was a survivor first and foremost; strong, stubborn, determined. But even just the notion that she was going through something that  _ required _ surviving… The thought made Mimi weak.

"...Do you trust me?" Sans gazed at her, brow line furrowed.

The question took her by surprise. "I—"

"I need you to trust me, Mimi.” His low voice had shifted to a more serious tone now.

Mimi nervously averted her eyes away from his gaze, focusing on her hands instead. There was a brace on her right wrist. The bruises on her left knuckles were still a faded purple, but the broken skin had begun to heal.

Of course she trusted Sans. But it was becoming more difficult to stay optimistic. She was losing hope with every moment that she didn’t have answers.

“...I trust you,” she finally affirmed.

Sans scooted even closer, twisting his body towards her like there was a magnetic pull between them. Mimi could feel her heart fluttering in her chest, his closeness somehow both calming and nerve-wracking at once.

"Hey.” He laid a hand on top of hers. “We're in this together now, alright? You're not alone."

Mimi nodded timidly.  _ Together. _

"And when we get your sister back, it won't be too late for her either. Alphys will help in whatever ways make sense. Then…” Sans pulled his hand away abruptly.

“Then she’ll escort you girls back to the Surface.”

Mimi froze. “You’re… making us leave?”

“Aly had the right idea - it’s time for you to go home. It’s not safe here. Never was.”

“But I have you—”

Sans shot up from the bed, quickly stuffing his hands deep into the pockets of his jeans. “If something happens, I can’t save you, kid. I couldn’t save Frisk all those years ago, and I can’t save Aly now.” His voice cracked under the audible emotional pain of his perceived failures.

“...At least let me do one thing right.”

Mimi’s heart ached for him. “Sans…”

He turned away from her. “Try to get some sleep, alright?”

“Sans, look at me,” she called out desperately. Her voice was cracking too, breaking under the pressure of finding any reason to make him stay. She didn’t want to be alone right now. She needed someone. 

She needed  _ him. _

“Kid, please…”

Maybe it was just as easy as asking.

“Sans…” her voice was still shaking, making it difficult to get the words out. “Will you…”

Finally, he turned back around and patiently waited for her to finish.

Anxiety quaked through her bones and tied her stomach in knots. But she had to. She had to ask. “Will you just... stay with me tonight?”

Sans’ eyes shrunk to pinpricks. He opened his mouth to speak, but no words came out.

Mimi could feel the tears again. She already knew the answer. God, she was so stupid! Maybe the embarrassment would kill her if the heartache didn’t.

Sans stared at her for the longest moment before taking his jacket off and tossing it onto the floor.

“Is that… is that really what you want, Mimi?”

It was already too late to stop the tears at this point. But underneath her swollen red eyes and uncontrollable weeping, she nodded.

“...P-Please… don’t go…” she gasped in between sobs.

Just as quickly as he had been prepared to leave, Sans was now back at her side again. He tenderly held a hand to her cheek and wiped away what tears he could. There were too many for him to keep up, but he tried. He always tried, and that was enough.

“...Not going anywhere, kid.”

*** 

It was an unending loop; a scratch on a record, a video stuck on rewind.

Death had become a dream, and Aly was never allowed to stay asleep for very long. The reality was much grimmer.

She didn't die. She  _ couldn't  _ die.

Determination continued to drip into her blood, now from additional entry points that Gaster had been working up to once Aly was desensitized to the blanket of unending torment.

The flesh was frayed around the new entry points on her back, haphazardly ripped in a vague rounded shape to accommodate these thicker tubes that kept her completely tethered to the machine as if she were merely an extension of it now. Bruised purple veins and blackened blood vessels snapped under the immense strain of overflowing liquid being forced in. Her left eye, now resuming its role in Gaster's twisted attention as the laughably metaphoric  _ window to her soul _ , felt like it was engulfed in a constant flame, melting infinitely out of the socket as the liquid dropped directly into the pupil. Aly could feel it seeping into the back of her skull; another splitting, incessant pain that she would grow too familiar with and despise becoming complacent with amongst every other ounce of pain her body was enduring all at once.

It was excruciating, but this was no longer the worst of it. Even her soul was made of wires now; the essence of her entirety unexempt from the relentless prodding and objectification. Gaster knew all along that there was an incredible power buried deep within Aly's soul that was being flooded out now: the power to reset. To go back to a predetermined point in time indefinitely. To never truly die.

And he knew how to use it. It was second nature to him, defining points in time to reverse to the moment Aly’s soul gave in. All so that he could fix his previous errors and start again.

Pain, death, reload. Tests, failures, do-overs. It went on like this so endlessly that Aly had completely lost track of time.

Gaster controlled it; abused it.

The worst came when her soul, resilient and determined as it was, refused to stay broken, even when she begged it to. Even when every fiber of her being wanted to remain dead, even when she pleaded with Gaster to just end it, she'd wake up again and again and again.

It wasn't her Determination that kept her alive anymore.

Aly was sitting up on the table now, hunched over the edge of it as a slew of tubes and wires dragged behind her, pulling and sticking to her hot skin. A mask attached to her face breathed life into her when she couldn’t manage. Electrodes connected to leads were stuck all over her body to measure every detail - her heart rate, her brain waves, her rising DT levels. The binds that left deep lacerations across her wrists were off because she was secured in place completely by machines now. And the longer Aly remained trapped beyond the automated hums and whistles of metal, the more she lost the right to call herself human.

Gaster remained preoccupied most of the time. He wrote endless notes, monitoring each machine simultaneously.  When her soul would give out, he would augment its abilities to bring her back, level with the losses… and then write more notes about it.

“How did it feel that time?” he would ask when she’d wake up, gasping for that first breath and then wishing she hadn’t come back to take it.

...How did he  _ think _ it felt? A terribly condescending question, one she never answered. But Gaster would keep pressing regardless.

Eventually, after one particularly difficult failure that knocked Aly’s DT levels to a dangerous low, he lost his restraint.

“Why must you insist on making this so difficult?” His voice growled as the darkness flared with him. Volatile, pretentious, impatient. Aly was seeing so many new sides to the doctor that came out with each unsuccessful attempt.

Even so, she refused to speak; to give Gaster the satisfaction of her answers. It came to the point that he'd raise his hands to communicate with her and she would never even look at them. There was nothing more he could ask of her than what she was already unwillingly giving him.

“Resistance will get you nowhere,  _ darling _ .” There was venom in the endearment now, and Aly wished she had either the strength or the courage to laugh. She hated it, anyway.

That was the last thing Gaster said before continuing in silence for a very long time. Just more pain, caustic and throbbing and raw. More death, again and again and again, then waking up from the dream and back into the nightmare. Perhaps the most detestable part about it was that Aly remembered everything. Every time her heart stopped, or her lungs collapsed, or her soul shattered - she took it all with her when the world stuttered and she returned. The phantom pains ached all over her body now, feeling organs failing and vessels bursting and bones cracking.

The causes of death varied and kept Gaster intrigued with each one. Aly wasn’t numb to them yet, not really. But she would pretend. For as long as she could still hold onto a shred of her own will, she would convince him that she had not been broken.

However, the hard reality of it was that she was already broken. Over and over again, he broke her, knowing that he could just put her back together again with little consequence. The extent to which Gaster had absolutely no concern for anything but his success sickened her. She was a toy, and this was a game. And when he didn't like the outcome, he'd start over until he won.

She would have rather been dead than face Mimi in this condition. And she knew the weight of her sister's own guilt if she saw her like his would tear them both apart.

Aly already had it in her mind that if she ever made it out of here, she wasn't going to go back. Perhaps that was a selfish choice, but Mimi had Sans now. He could pick up the pieces and make her whole again once she was gone.

At long last, the silence between them ceased when Gaster's voice cut through the void.

"This is it."

He had finally made a breakthrough.

Aly's soul beat erratically outside of her body, enlarged and bursting at the seams from being forced to carry more Determination than it could handle. This is what Gaster wanted. Aly could tell from his raised expression now that this was a good thing to him. Her soul, though at its limit, was no longer breaking under the pressure. It adjusted, death after death, coming back more resilient each time. Until finally, it refused to break at all.

Gaster was so pleased, grazing a finger against the glassy surface of Aly's soul. She flinched at the contact, like ice against fire. Souls were fragile, and hers was hyper-sensitive from the long exposure outside of her body. Each pump of DT pounded like a hammer. Each touch was as sharp as knives.

"It's ready."

Aly remained silent behind her troubled breaths into the oxygen mask. She could feel Gaster gazing at her, so she returned one quick glance before letting her defeated eyes fall again.

Gaster gripped Aly's soul roughly in one hand, pulling the wires dangling from it with another. Aly lurched forward and choked for more air each time it was pulled, the throbbing pain taking her by surprise. She could feel every crevice and indention of his fingers wrapped around its diameter, gaping palm pressed against the core. Aly involuntarily let out a raspy whimper from the pain.

“Do you know what comes next?”

Aly nodded once, but said nothing. This was what she saw from her father’s eyes. This is where he died.

So what was the fate of someone now that was incapable of staying dead?

Aly did have one question for the doctor.

“What…” she wheezed from behind the mask. “What are you going to do once you've fused the souls…?”

Gaster was taken aback by her inquiry. This was the first time he had heard her speak since the beginning of this endeavor.

“Leave this place.”

“And then…?”

“I suppose I haven't figured out the rest yet.”

...He didn't know.  _ Hah. _ All this trouble, and the brilliant W.D. Gaster didn't even know why he was doing it. Perhaps he had a larger goal in the past, but years of sitting idle had turned this mere idea into an empty obsession.

It had become more difficult to hate him completely beyond how terribly sorry Aly felt for him now. This experiment was all he had. Hurting her was all he knew to do.

Living beyond the Void was much more complicated.

Gaster held on to Aly's soul, pulling it further from her body as he stepped away. Aly could still feel it oscillating in his hand, yet she could also feel the uncomfortable pull as it left her side. She never knew a human soul to be tangible, something you could pick up and leave with. That notion should have made a soul all that more important to protect, and yet, here she was, just allowing the monster torturing her for his own selfish gain to just... walk away with it.

How did everything come to  _ this _ ...?

Gaster returned from the shadows after a moment with two glass containers in his hands. One housed Aly's red soul, but she turned her attention towards the  _ other -  _ the artificial soul created from his very own core. It's glow paled in comparison to her soul and was still laced with hairline cracks and bubbling black stains. Aly learned that a human’s soul was always associated with a color and that a monster’s soul was always gray. What Gaster and her parents had created was nothing like either of those.

The machine to finish the job was the newest out of all of them, built completely by her mother and father ten years ago and reconfigured by Gaster after their failures. An overly simplified design compared the elaborate features of the DT Extraction Machine that was constructed in the intimidating shape of an animal skull. There were no exposed wires, no complicated controls. Just a large metal structure with two ports to house the glass soul encasements and a large extending arm with a barrel at the end that reminded Aly of a trip to the dentist. …A dentist that she may never leave from with all of her teeth intact.

"This is where the true test begins." Gaster was behind her now, examining the tubes in her back.

Two hands still held the souls, two more translated as he spoke. Without warning, two more grabbed ahold of the tubes and ripped out the prongs that kept them latched to her skin. Aly gasped, a screeching wail followed as the spiking pain intensified over the course of the next few seconds. Tremors shot through her spine as she felt trails of excess liquid oozing out of the wound and down her back.

She reeled backward as she desperately gasped for air into the mask. She choked as the oxygen couldn't flow fast enough to keep up with her hyperventilating. One thing after another; ache after sting after burn. Aly had long wondered if Gaster got any sort of depraved enjoyment from putting her through this.

The doctor was 'kind' enough to tend to the lesions, wiping the excess fluid before properly bandaging them. One by one, he went to each of the tubes to remove them. Aly's veins were engorged, swollen and black underneath her flesh. They throbbed as the needles were pulled from them, convulsing with spurts of DT and blood before Gaster wrapped them as well. Aly let her arms fall limp at her sides, incapable of even lifting them now that she was free to do so. Her entire body was heavy, as if lead had completely replaced her blood.

"You may want to lie down for this, darling," Gaster urged.

Aly's entire body quaked as she barely managed to lift one finger up and point towards her left eye, still pried open with a needle secured into place by another bandage around her face. 

"You'll need that one," Gaster exclaimed passively and with no further explanation. "Now, if you will." He gestured to the back of the table, reminding her once again to lie down.

Aly silently complied and struggled to shift her body around to rest on the table. Every limb was stiff from sitting in the same position for... hours? Days? There was no telling how long it had been anymore. It was almost a relief when she set her head down and stretched out her legs; a tiny reprieve from the living nightmare.

She closed her one good eye, focusing on her heartbeat again. For the first time in too long, she thought of Mimi. Her sweet, sweet sister. Aly didn't want to dwell on the thoughts for too long - she couldn't afford to get emotional right now. Emotion was weakness here; just another opportunity for Gaster to get under her skin.

_ I'm sorry, sis. _

Maybe there was some merit to forgetting the ones you love instead of suffering through the loss of them. Maybe the Void would do that for her, too.

When Aly opened her eye, she was met with the barrel of the machine's arm hovering directly over the point on her chest where her soul was accessed. Meanwhile, Gaster was sliding the two encased souls into the available slots on the main control panel. She could still feel it beating paces away, heavy with Determination, just trying to survive this as much as she was.

She could hear the machine whir to life, the arm above her heating up and making the air around her dense.

"What if... this... doesn't work..." Aly breathed the words out lifelessly as she exhaled.

"Then we continue until it does." Gaster continued to man the control panel, adjusting dials and levels for each individual soul.

Of course. What was the point in even asking?

After all, what was there to lose when you could just start over without repercussions?

As the machine hummed louder, Aly's hands began to shake uncontrollably. As much as she had surrendered to the situation, she was still nervous. No, more than that - she was terrified. What was life going to be like if she made it through this? Would she retain even a portion of who she was now?

There was no more time to think about it. It was happening.

Aly turned to face Gaster, who was affixed on the souls inside the machine. Their glow from behind the glass was blinding, illuminating a large radius around it. The arm over Aly began to vibrate and a faint red light seeped out from the barrel. She was scared to move, scared to do anything at all, tensely waiting for whatever this was going to feel like.

Suddenly, the light at the end of the opening charged for a moment before shooting directly into Aly's chest.

It didn't pierce the skin at all, but it  _ hurt. _ Not nearly as bad as the DT injections, but it was a suffocating pain that billowed through her lungs. It filled her chest as she struggled to breathe, burning through her oxygen before she could inhale it.

_ Just stay calm, _ Aly tried to remind herself through the panic.  _ Just keep breathing. _

This pain felt eerily familiar. As she clamored for her next breath, she recalled this feeling... from her dreams. The very first time she 'met' Gaster in her sleep, the darkness suffocated her like this. She couldn't seem to avoid it then, either. 

As the heat of the light stream crept through her body, her bandaged left eye began to throb and pulse against the needle embedded in it. It was reacting to the energy, and she had no idea what was happening.

"G-Gast-ter..." Aly called out weakly.

Gaster manifested at her side, shifting his gaze between the flow of the stream and her eye.

"Interesting," was all he had to say.

"W-What's... happening...?"

Even he didn't seem to have answer.

Her eye began to sting, and then burn. And suddenly, it was unbearable.

"Gaster,  _ please _ !" Aly let out a shrill, desperate scream as she gathered the strength to reach for her face and claw the bandages away from her eye.

Something was wrong. Very, very wrong. But as Aly reached for the thin needle meticulously centered in her pupil, her hand was stopped by one of Gaster's.

"Don't," he warned.

"M-Make… it… st-top…”

"Stay strong, my dear." For the first time, Gaster was being decent. Maybe even he didn't anticipate this. “The Determination is reacting to the new soul being created. It would be dangerous to stop it.”

The burning didn't get any easier to bear. It started in her eye and moved through her everywhere that Determination flowed. She could feel it in the back of her skull, in her veins, in her bones. 

Most of all, and as strange as it was, she could feel it in her hands.

The ability to cry that Aly thought was long gone had been found again. In between the tears and the sweat and the blood of her fresh wounds reopening, she screamed in a fruitless attempt to relieve the pain. The fire was building up like a ball in her chest and she didn't know how to release it. She pleaded with Gaster over and over to make it stop. And, while it did elicit a surprising amount of emotion from him, he refused to do so.

"The fusion is working, Aly. We cannot stop now."

This was the exact moment when her father's soul could no longer take it - she remembered that much. Gaster pushed and pushed, and he went too far. He was going too far with her too, but refused to acknowledge it.

It was different from before. Her soul wasn't going to break, it was going to  _ burst _ . Was there any coming back from  _ that _ ?

Aly couldn't take it anymore. She focused hard on the energy in her chest, hard enough to almost grasp with her bare hands. She used every fiber of strength to channel it through her tired, heavy arms and into her palms. She had no idea what she was doing, but she could feel it;  _ control _ it.

But then it slipped.

Instantaneously, there was a loud booming crash behind her, coming in tandem with the second she let go of her focus.

“W-What was that…?!”

Gaster's voice roared across the Void, something she couldn't translate. But it wasn't anger.

He was... laughing.

Aly searched for him in her peripherals, but he was no longer beside her. She assumed he was in the area where the crash came from. However, as much as she called, he did not answer.

The energy kept reconstructing itself in her core, manifesting and then releasing. It did this several times, recycling its essence inside her to reshape over and over. It was incinerating her insides, but she was growing used to the feeling. Eventually, it was starting to feel like… it belonged there.

Her soul was returning to her. Gradually, it grew. Stronger. Fiercer.

The machine was at maximum capacity, its arm vibrating violently as it struggled to stay centered over Aly’s chest. 

“How…much… longer?” Aly choked out.

No answer.

For once, she was desperate for a response from him. “Gaster…!”

Nothing.

Aly’s shaking arms reached up towards barrel of light and grabbed it with both hands. The hot opening seared her palms as she struggled to direct it away from her. It was heavier than she thought, or maybe it was just that her body was too weak.

She screamed as it burned the skin right off her hands… another familiar pain. But if Gaster wasn't going to stop her, she was going to fight back one more time.

_ Find it.  _ Aly reached for that energy again. And once again, her eye reacted to it, pulsing and flaring as it built. With one hand, she unclamped the wire from her cornea and yanked it out as hard as she could. The long, thin needle painfully shot out from her pupil, rupturing nearby blood vessels on its way out. Another scream, more blood mixed with oozing Determination.

Aly clutched at her chest where the light was still hitting as if physically trying to release the knot that tangled her insides.

_ Find it. _

There.

She concentrated on the heavy feeling of what she hoped was her soul returning to its rightful place in her body. The energy was wrapped around it, keeping it hostage from her.

_ Get. Out. _

To her astonishment, it listened. The energy unraveled itself from her chest, down through her arms and into the palms of her hands again. She was holding this invisible force, like a bomb about to explode.

So she let it go.

In that moment, a mass she could not see sped forward from directly behind her and cannoned into the arm of the machine. It boomed and crashed on its way down, completely severing from its base. The barrel that was too heavy for Aly to move prior came tumbling down - almost in slow motion as she saw it happening but could not move quick enough to avoid it.

The reverberation of collapsing metal exploded through the Void. And when the dust settled, it was nothing but darkness once again.

 

It was unclear whether or not Aly had actually survived the accident on her own accord, or if her death had triggered another reload.

Regardless, she was alive.

She was on the ground now, trapped under the metal beam that fell on top of her. With a free arm, she reached for her face, ripping the broken oxygen mask away from her mouth and feeling around her eye. Thick red liquid smeared against her face, still as vivid as the pain.

And her hands. Both were charred and blistered from the contact with the machine. Circular scars from pressing  against the gaping barrel where the light stream radiated were imprinted on the tops and bottoms of her palms.

How grotesquely ironic.

Aly tried to shake herself free from the debris. She slid against shards of broken glass and shrapnel until she made a gap big enough between her body and the beam to inch her way through. Her clothes were drenched in blood, an open gash sliced across her chest directly where the metal arm had fallen on top of her. It hurt, but it was just another addition to the long list of growing physical pain that Aly was burdened with.

Once she was completely free, she wasted no time heaving herself to her feet. However, standing didn't come easy. Glass crunched under her boots as she staggered up, one foot at a time. She latched onto the dented operating table for stability and examined the damage in front of her.

Everything was destroyed.  _ Everything. _

The machine her parents had created was in pieces. Live wires sparked and snapped, tubes mangled around metal. The DT Extraction Machine had been cracked right down the center, one side of it dragging against the ground.

More peculiar was the cause of all the damage. Monstrous bones, lodged deep into the metal, with ends sharp enough to pierce through the material effortlessly. Grisly exposed muscle wrapped around some of them in flayed ribbons. Some of the larger ones had cracked on impact - those cracks discharging a steady drip of red fluid.  _ Not blood. _

Did Gaster do this? Aly scanned the dark for the doctor. Every machine had fallen to the same fate of these bones - demolished and irreparable.

Through the wreckage, she saw him, leaning over his desk on the opposite end of the room.

Did that mean the experiment had failed? Did she stop it before their souls could finish fusing?

Aly cautiously limped across the room, smears of blood from her shoes creating a trail behind her in the broken glass. 

“Y-Y-ou-u…” she hissed as she approached him. She could see Gaster’s silhouette shift when she addressed him. She expected to see his hands rise up to give her some sort of long-winded explanation for his actions (and lack thereof) that she didn’t want to hear. However, her anger was cut short by confusion; a voice in her head… that wasn’t hers.

**_At last._ **

Aly froze. The voice was completely unfamiliar to her; deep, smooth, concise. Impossible.

A moment passed, and the voice undulated in the back of Aly’s head with a low laugh. But… it still wasn’t hers. 

She glared at Gaster. His shoulders fluidly moved up and down as if he were laughing as well.  “...What have you done to me?”

Slowly, Gaster turned towards her. When his face met Aly’s, she reflexively stumbled back a couple of steps and looked on in horror at his change in appearance.

He was… melting.

Like a malleable substance put to a flame, pieces of Gaster’s skull and body bled over itself. The liquid ossein welled in his sockets and over the deep cracks below them. His body dripped like black tar over the papers on his desk. 

And there was that laugh again, vibrating her skull, driving her mad.

**_We’ve done it._ **

Still beside herself in shock, Aly was having a lot of trouble putting the pieces together.

“Is… Is that  _ you _ …?” she whispered to Gaster’s dissoluting figure, but referring to that incessant extra voice that echoed in her head.

The voice responded just as clearly as before,  **_You seem surprised, darling._ **

_ No. _

No no no, this wasn’t possible.

‘Surprised’ certainly wasn’t the word for it. Aly was mortified, frozen in place by the dread that shot through her body.

“I-It worked…”

Gaster was grinning beyond his oozing skull.

**_This success has exceeded every expectation._ **

Aly’s eyes widened. No. This was wrong. Gaster was still here. She still felt like herself. She still processed her own thoughts, which appeared to be completely separate from the extra voice. 

“But the machine—”

**_It was already done by the time you destroyed it._ **

Aly glanced back at the wreckage. “Wait,  _ I  _ destroyed it…?”

**_Surely you felt that magical discharge from the soul reconstructing itself._ **

Magic. Yet another impossible human feat that Aly refused to believe.

Gaster read the skepticism plastered all over Aly’s face.  **_Remember, this isn’t just_ ** **your** **_soul anymore._ **

“It still feels like it.”

**_Then take a look._ **

He pointed a dripping finger up towards her chest.  **_Summon it._ **

“I can’t—”

**_But you will._ **

Aly scowled, frustrated that she had way more questions than answers at this point. This was all  _ wrong.  _ How could she even be speaking to Gaster like this, understanding his voice so clearly now as if it  _ were _ her own? How was he still standing in front of her, demanding things of her when, in all honesty, she seemed to be in better shape than he was? Not only that, but humans couldn’t pull souls like monsters could - she didn’t even know where to begin. So many questions, never any answers.

But fine, she’d been forced to play his game up to this point. Compliance, even with as long as she had spent defying him, came much easier than the consequences of not doing so.

Aly tried to find it again; that feeling in her chest. Magic, according to Gaster. It was still such a foreign concept to her.

...There it was. She was better at pinpointing it this time, slithering around her soul like a predator circling its prey. This time, instead of channeling the energy down to her hands, she concentrated on gently wrapping it around her soul like a blanket. Not enough to hurt, just enough to move it. This took a bit of effort. And judging from Gaster’s dilapidating state, she was running out of time to figure it out.

Her chest tightened. _Got it._ _Now just…_

Aly’s fists clenched and twitched as she tugged internally at her soul. She started gently, but it refused to budge. Gradually, her hold grew tighter as she pulled a little harder each time.

At last, with one firm heave, the soul appeared outside of her body.

“...Whoa.”

**_Excellent, darling._ **

The soul was completely unrecognizable from before. Its rhythm pattern was irregular and sporadic, as was its form. It vaguely resembled a heart, but with deep fissures that misshapened it. From the cracks gushed black sludge that darkened its weak red glow. 

It was struggling to retain its place as  _ her _ soul, but it was being overtaken by his. It didn’t feel any different. However, physically seeing her soul in this condition made Aly sick. It made her head spin, the sight alone making her want to pass out. With a swipe of her hand over it, it dispersed back into her body much quicker than it took to coax it out.

**_Do you believe me now?_ **

Aly did. She didn’t want to, but she did. 

“What does this mean for you…?” she asked quietly, still holding out for an explanation. Gaster was in worse shape now. It was a slow process as his body melted like molasses, but it was taking its toll. Eventually, there would be nothing left.

A guttural chuckle escaped his body as it shifted towards her with gushing, sodden footsteps that stuck to the ground. Even as it sagged, he still towered over her menacingly by several inches.

**_This body can no longer sustain itself without the core I imbued into the artificial soul,_ ** Gaster explained.

**_But I do not consider this a loss. My memories, my abilities, my essence…_ ** His eroding grin grew wider as he tapped a finger against Aly’s skin between her collarbones, just above the open wound across her chest.

**_It all lives within you now._ **

Aly stepped back, aghast with Gaster’s physical presence standing too close to her now.

“And what about this place?”

**_It will all disappear with this body._ ** Gaster slowly rotated his body towards the adjacent wall. The door back to Waterfall was visible again.  **_So you’d better leave while you still can._ **

Hah. Leaving was that easy now; as easy as walking through that door. So easy, that Gaster was now  _ urging  _ her to do so for her own safety. ...Or was it for his?

Regardless, Gaster didn’t have to tell Aly twice to leave. Without even looking back at her captor’s body, or her parents’ creations, or a single other part of the Void, Aly limped towards the door and used all of her remaining strength to pull it open and shut it behind her for the very last time.

 

Aly immediately collapsed when she felt Waterfall’s crisp air against her bare skin again. Her back ached against the cavern walls, but its cool surface was like an ice pack on her wounds. She breathed shallow breaths back into  _ this  _ reality, a world she felt completely separated from for so long. Time did not exist in the Void - nothing did. To be back to this point in time and space, right here, grounded by the smell of damp grass, the sound of running water, and the light of the bioluminescent vegetation… it was overwhelming.

She was alive. She had experienced Hell and everything that lies beyond it, and yet she made it out alive.

But at what cost?

The gravity of her situation was beginning to set in. She wasn’t the same, nor would she ever be. She was… broken. Torn apart, then reconstructed into something that teetered in a purgatory between humans and monsters. This wasn’t a dream she was going to wake up from. This wasn’t a game she could—

_ Reset. _

What determined the point in time that her soul would reload to when it shattered? Aly assumed it was up to Gaster’s discretion while he had control of it through the DT Extraction Machine. But what about now that she was back in control? What if she could use it indefinitely? What if she had the choice to go as far back as never having to encounter Gaster at all?

Aly had to find out.

She stumbled back to her feet and began to walk. Not in the direction of Snowdin - she remembered her resolve to never go back there.

Aly had never traveled this far east before, beyond the dark, winding caverns of Waterfall.

**_Where do you think you’re going?_ **

Gaster’s voice startled her. She had already forgotten that leaving the Void no longer meant escaping him. Her soul was his now, too; the nightmare she could never outrun.

“I don’t know.” That was the truth. Her makeshift plan to test her soul’s durability was being based solely on instinct.

**_I imagine you want to see your sister._ **

Aly grimaced. Of course she wanted to see Mimi. Just… not like this. Not when she wasn’t really herself anymore.

She let out a sarcastic leer. “You don’t know what I want.”

**_Perhaps you’re right_ ** , Gaster conceded.  **_I cannot read your thoughts. But I can feel it in your heart._ **

“I’d rather you not.”

**_I’m afraid neither of us have a choice in the matter anymore._ **

Aly faltered. “No, you  _ always _ had the choice.” She looked down at her hands, trembling in a combination of pain and anguish. The circular burns disgusted her in a sardonic sort of way. Not only did she have to carry the burden of Gaster’s existence with her, but now she had to wear these scars as a constant reminder that, in the light of what he considered a success, she had failed. “You stole that from me.”

**_I have made you powerful._ **

“I don’t want power.”

**_Then what_ ** **do** **_you want, my dear?_ **

“Answers.”

The caves ended and another drastic climate change awaited Aly on the other side. It was hot. Dense, suffocating, unbearable heat. She was on higher ground now; cliffsides overlooking gurgling pools of lava.

_ Perfect. _

Aly started toward the edge of the closest cliff. As she approached it, the heat beat down on her harder.

Gaster had caught on.  **_Aly. Stop this._ **

Sweat beaded underneath her bangs as she moved even closer, disregarding Gaster’s voice.

**_You will accomplish nothing._ **

Finally, she was standing over the edge, looking hundreds of feet down into the bubbling flames. “You can’t stop me anymore.”

**_That’s where you’re mistaken._ **

Suddenly, she felt a sharp tug in her chest; a shift in gravity. Before she knew it, she was on the ground.

Aly knew what this was without even having to see proof of it. Gaster’s blue magic.

He still had control.

Aly groaned from the impact of her broken body on the scorching hot soil.

“T-This… isn’t… fair…” she spat through her teeth.

God, she  _ loathed _ him. She was a prisoner in her own body, stripped of even the most fundamental choice to live or die.

**_I’m not going to allow you to kill yourself._ **

“That’s  _ rich.”  _ Aly laughed herself nearly to tears, still pinned to the ground by nothing but the weight of her own body. She was still so close to the edge, one of her arms dangled limply over the stale air of the canyon. All she needed was one little opening in his grasp... 

“So you care about me now, is that it?”

**_Your soul wasn’t strong enough to perform a reset on its own to begin with, and there is no telling if this new soul even bears the same trait as yours. If you die, you may not have the opportunity to return. And then this will all have been for nothing._ **

Maybe that’s what Aly wanted - for all of this to be for nothing. One last chance to take away the satisfaction of success from Gaster. Why would her father ever have consented to this? The reverberation of this extra voice in her head was maddening. This arrogantly dismissive, sadistic, callous voice that belonged to a monster that was even more so. All he saw her as was the most promising science project in a decade.

Aly refused to live another second like that.

She felt the magic holding her down begin to fade. His guard was down once again, but she wouldn’t have more than a second to act.

One last chance.

_ Don’t make me come back. _

The very moment she was able to move again, Aly pushed both feet off the ground as hard as she could and flung herself over the edge.

  
  


**_You foolish girl._ **


	13. The Aftermath of Success

**Summary for the Chapter:**

> Aly is having trouble regaining control of her new soul. The sisters are finally reunited. Alphys wants to run more tests.

**Notes for the Chapter:**

> Wow. Sorry for the unexpected hiatus - it's been a tough two months for the both of us. But we're back, and that's what matters. Head over to our [Tumblr](http://anundertaleoftwosisters.tumblr.com/) to see what's been going on since the last chapter.
> 
> Just a few things:  
> -Thanks for 900 hits! It's not much, but way more than we ever expected to come of this. Just hitting 1000 will be a huge accomplishment.  
> -These later chapters are much longer than we expected, but we're still hoping to finish this up by the end of the year.  
> -A very dear friend Dark_Crystal_Demon started her own (NSFW) UT fanfic, with elements directly inspired by Undertaken! It is phenomenal and ended up influencing quite a bit of this chapter in return. I can't say enough good things, so just go and [check it out for yourself.](http://archiveofourown.org/works/7775452/chapters/17734651)

**_Get up._ **

Aly wished that voice in her head would just stop already.

But it didn't. It pressed against her temples until she was forced to open her eyes.

There she was, back on the damp ground in Waterfall, leaning against the cold stone walls - unscathed by the fire and brimstone below the cliff side that she could still vividly remember.

...So this was as far as she could go. There was no returning to a point before this, and remaining dead still wasn’t an option.

She was stuck with _him._

Aly’s entire body ached as if she were feeling her injuries for the first time. It became harder to find the willpower to stand up and walk again.

However, Gaster insisted. **_You're going to get up._ **

Aly leaned her head back, exhausted at the prospect and even more exhausted with Gaster’s demands.

“I can't.”

Gaster scoffed, audibly frustrated with Aly’s constant concessions. She found herself saying this at every turn now, defeated and empty of any other feeling. His voice was a growl brushed with malice - most likely also disapproving of the reset stunt that placed them back here.

**_You have learned nothing, Aly._ **

Oh, she had learned plenty. Too much, even.

“I’m not your test subject,” Aly boldly repeated her sentiments from before she jumped. “You don’t get to control me anymore.”

Gaster repeated his as well, **_I beg to differ._ **

Suddenly, the flare in her chest returned; magic lighting up her soul with an all-encompassing visceral flicker. However, it was the opposite of blue magic. Instead of the weight of gravity holding her down, it lifted her back up to her feet like she suddenly weighed nothing. With one involuntary step after another, her body was moving on its own.

“W-What are you doing?!”

**_You’re trying so hard to convince yourself that none of this happened, aren’t you?_ **

Another painfully unwilling lurch forward. Aly tried to force herself to stand still, but the new, unfamiliar magic was overpowering.

**_So you choose to be reckless._ **

And another.

“Gaster, s-stop—”

The grip on her soul was starting to hurt. If she didn't know any better, she could almost feel Gaster’s sharp touch prodding her soul, unnecessarily rough just to force a reaction out of her. With each squeeze, her legs stumbled another few steps.

**_But remember this, my dear; your entire existence is an experiment. And I am the only one that can help you find the answers now._ **

“Let… go— _ngh—”_

Her body promptly stopped moving after her last plea. However, the magic wrapping itself around every muscle and bone didn’t let up. In fact, it was getting… stronger.

**_Have you stopped to think about why this power lives within you now?_ **

To be honest, Aly hadn’t had time to think about much of anything since leaving the Void. Which, considering the reset, _just_ happened moments ago. Her silence was enough for Gaster - he already knew the answer to his mostly rhetorical question anyway.

**_It’s my magic, successfully integrated with a human soul in ways monster science deemed impossible. You need to learn how to control it properly._ **

Aly was feeling far too bold again. The truth was that her surrender was still thinly lined with animosity. “No.”

**_No…?_ **

_Stop talking, Aly._

But she couldn’t. “I didn’t agree to any of this.”

**_I’m afraid it’s a little too late for formal agreements, darling._ **

Another tug at Aly’s soul and the energy was snaking it’s way down her arm again and pooling in her right hand. The fact that she wasn’t controlling any of it this time terrified her.

 ** _Tell me_** , Gaster crowed. ** _What exactly is it going to take for you to stop being so insolent?_**

This was bad. Aly stood motionless, still lacking any control over her limbs. Meanwhile, Gaster’s magic was suffocating her insides, waiting fervently to be released. Her arm was heavy with the invisible force wrapped around it and her blinded eye was reacting painfully to the sparks of energy.

“What more do you want from me…?” Aly’s conscience teetered on a fine line between brazen defiance and crippling fear of him. At this moment, Gaster’s grip on her was so insufferable that she would concede to anything to make it stop.

 ** _I suppose the longer you spend in solitude, the more things you realize you want_** , Gaster mused. **_But right now, above all things…_**

**_I want you to remember that this is my soul now, too._ **

The magic hooked around every individual finger on Aly’s hand and constricted them so tightly that they began to go numb.

“N-No, wait…!”

Without warning, the magic encompassing Aly’s hand snapped, forcing each finger backwards at its joints.

Aly wailed as the phalanx bones splintered underneath her skin. She cursed Gaster as control returned to her limbs, all the way down to the bent extremities.

**_Have I convinced you yet?_ **

Aly couldn’t speak beyond the renewed pain shooting up her arm. She pitched forward and stumbled to the ground as her own weight returned around her. Eventually, even her screams subsided and the pain deafened everything.

 **_Well?_ ** Gaster was no longer taking her refusal to acknowledge him as an answer.

“...Y-Yes…”

How was it possible to hate him even more than she already did?

**_You should really be grateful for what I’ve given you, Aly. This discovery would have changed everything back then._ **

_Back then._ As if it even mattered now.

That was Gaster’s inherent flaw; he did things just to see if he could, not necessarily that he should. And now that it was done, he had no direction. It was as if the mind of God had created the universe and then run out of things to fill it with.

 

Aly’s screams must have caused more of a ruckus than she had hoped. Unbeknownst to her, she had attracted the attention of one of the monsters stirring around the area.

The one monster her heart couldn’t handle facing right now.

The tall skeleton faltered when his gaze met Aly’s. She hadn’t seen herself in a mirror recently, but she was sure her appearance must have been jarring. For a solid minute, Papyrus stood there, silently examining her features. He opened his mouth a couple of times to try and speak, but the words wouldn’t come out.

Aly finally started before him, “Papyrus…?”

 **_Papyrus_ ** , Gaster echoed immediately after hers as if their voices blended into one. He seemed almost as taken aback as she was.

Papyrus’ eye sockets lit up with a strange combination of awe and horror that contorted his skeletal features in unrealistic ways.

“A-Aly…!”

And for the first time since this ordeal began, her heart was heavy.

For a fleeting moment, it felt _whole_.

Without even realizing when it began, Aly was crying.

Within seconds, Papyrus was beside her on the damp ground as she sat on her knees and sobbed. He held her steady with his hands gently bracing her shoulders, but the physical contact only made her weep more. It was as if her body had forgotten how to process emotions. And now, suddenly, there was too much of it when she saw him. He asked arbitrary questions about what happened, about how she got here, and about the broken fingers on her hand. However, Aly couldn’t focus on answering any of them. Her mind was clouded by the gravity of Papyrus’ presence pulling her even further back into reality. And she welcomed it completely.

Surprisingly, even Gaster was letting her have this moment in peace.

“We have to take you to Dr. Alphys,” Papyrus exclaimed. He took his scarf off and draped it over Aly’s arms, still haphazardly wrapped in stained bandages. The scarf was lined with his lingering warmth as Aly used her good hand to pull herself closer into it.

“The Royal Scientist…?” Aly sniffled.

 **Former** **_Royal Scientist._** Gaster’s mumbling voice corrected her.

“You're badly injured,” Papyrus continued. “She’ll help you. I'll call Sans and Mimi at once to—”

“No…!” Aly pushed away from the skeleton in protest. “Mimi… she… can't see me like this.”

“Aly that's ridiculous. She's your sister, she just going to be overwhelmed with joy just to see you _alive.”_ Without even asking for permission, Papyrus gingerly lifted Aly up and onto his back. She was too tired to fight it as he started in the direction of Waterfall’s eastern exit. Instead, she wrapped her arms around his neck and let her body relax. Despite feeling the bones of his vertebrae uncomfortably pressing against her chest, Papyrus was warm. Nuzzled in between his scarf and his body, she could almost forget everything that had happened.

_Almost._

“Do you… want to talk about anything?” Papyrus asked as he walked.

“No.”

“R-Right. I suppose you must be exhausted.” He paused. “I'm just… so thankful you're safe, that's all.”

It wasn’t much more of a walk before they reached the edge of the damp caverns again and into the land of unbearable heat. Aly’s stomach churned when they passed the cliffside from before.

_So stupid._

Alphys’ lab wasn’t much farther beyond a long wooden bridge that connected the cliffside to another; its rickety planks and rope railing being the only things in between them and a river of flowing lava down below.

Papyrus stepped confidently over each plank as the bridge creaked underneath his boots, a path he had probably tread hundreds of times before. Knots wrenched in Aly’s stomach as they crossed, but immediately settled once they were firmly back on land just as quickly as they had left it. Papyrus’ long legs had their advantages when trying to get somewhere quickly.

The stark white building that towered over them didn’t quite fit in with the exposed mountainsides of cracked basalt and volcanic rock. A hot red glow illuminated the entire area from below and gave all of the stone walls an overbearing warmth that didn’t quite reach the cold, sterile structure.

The metal door at the front of the building opened automatically when Papyrus stepped close enough to it. Even though Aly was expecting to be assaulted with cool air upon entering, the air inside was still stale and hot. Clearly the inhabitants were not bothered by the temperature of these parts.

“Dr. Alphys, I've found her!” Papyrus called out as he carried Aly briskly through a wide hallway lit by blinding florescent lights above them. He stopped when they reached the end of the hall that opened up into a sizeable vestibule, completely empty with the exception of a small desk and an inactive computer that took up a large portion of one wall. On the opposite end of that same wall was another metal door and what looked like an unmoving escalator.

The doctor emerged from the metal stairway, her broad tail thumping down behind her.

“O-Oh my…”

Aly peered over Papyrus’ shoulder as her tired eyes met Alphys’, a reptilian monster whose yellow scales shifted as she nervously adjusted her thick, round-framed glasses.

“She’s in bad shape, Alphys.”

“T-Take her upstairs,” Alphys stuttered nervously. “The lab isn’t r-ready yet. I wasn’t expecting this so soon, honestly…”

Papyrus nodded and rushed past Alphys towards the stairs. The short, scaley woman, dressed in an open lab coat over an oversized graphic tee and high-waisted shorts, sheepishly averted her gaze as they walked by. Aly would have never guessed she was once the Royal Scientist to the King of the Underground.

“What lab is she talking about…?” Aly whispered to Papyrus, concerned.

“It’s nothing to be worried about. Dr. Alphys just wants to make sure you’re alright after…” Papyrus’ voice trailed off.

Aly perked her head up. “...Do you… _know?”_

She could feel his bones stiffen like a muscle reaction, sans the muscle.

“Only what my brother told me,” Papyrus wavered. “But… you look far worse than any of that…”

 _Sans knows._ Of course he did. He probably knew even before Aly did.

_He knew and didn’t stop me._

“I don’t want to see either of them,” she mumbled.

“...I already texted Sans on our way here.”

Aly didn’t even see Papyrus pull his phone out this entire time. Even out of the Void, she was having a hard time keeping track of things around her.

She sighed. “Well… promise me you’ll at least give me some time before I have to face my sister…”

“Of course,” Papyrus assured her. “I’m sure Mimi will understand.”

Papyrus crossed the threshold onto the second story, a room almost as large and as empty as the one below it. They were immediately greeted by a wall of bookshelves off of the staircase. Most of the shelves were empty except for a few thick textbooks covered in dust. At the opposite end was a bed beside a spacious work table. Tattered corners of posters that once hung on the walls were still pinned in place.

Papyrus gently set Aly down at the edge of the bed and dusted off his uniform.

“Thank you.” Aly winced as she tried to pull his scarf, still wrapped around her, back over her shoulders.

“Your hand.” He pointed to the disjointed fingers on her right hand as it fumbled to pull over the scarf. “What happened?”

Aly couldn’t think of an excuse in time. “Gee Paps, out of everything else that’s wrong with me, _that’s_ what you point out?”

“I’m sorry, it just looks… so painful.” Papyrus knelt down in front of her and rested her injured hand on top of his. “At least let me help a little.”

The contact startled her. “Papyrus, what—”

The palms of his hands were resonating with a soft warmth as a low green glow wrapped around her hand and crept along her fingertips. It didn’t hurt like Gaster’s magic; it was kind and gentle, even as Aly felt the bones underneath her skin repairing themselves back into place.

“My healing magic isn’t the best, but it should relieve some of the pain,” Papyrus explained as he focused on guiding the magic delicately through each crack and joint. Once her hand retained its former shape, Papyrus released it and the magic dissipated.

Aly still couldn’t quite bend her fingers, but they were no longer broken. The relief was washing over her too overwhelmingly.

“Does it feel better?”

A response couldn’t come faster than the unwarranted tears did.

“I’m sorry,” Aly choked. “I-It’s much better, thank you.”

“Aly, if there’s anything else I can do—”

It hurt that Papyrus was so kind and she didn’t deserve any of it.

“I just need to be alone right now.”

His wounded expression hurt her even more. But true to his understanding nature, Papyrus simply nodded as he stood back up and flashed a smile at her. “Take as much time as you need. We’ll all be waiting for you when you’re ready.”

As Papyrus made his way back down the stairs, Aly began to wipe her tears away delicately with the very edge of his scarf. The coffee stains she had left on it before were faded, but still visible.

**_You can only push him away for so long before he leaves for good._ **

Gaster’s voice was something Aly knew she was never going to get used to. She felt crazy and surely _looked_ crazy talking to herself.

“Maybe it’s for the best.” Aly’s heart sunk at the thought. She had grown closer to Papyrus than she expected to. But her soul was far too crowded now to return even a fraction of his kindness.

“You’ve taken everything away from me.”

**_But imagine all of the things you can take in return._ **

That was his game. Even when she had nothing left to give, Gaster continued to take. He had some twisted fixation on it that Aly didn’t even think _he_ realized had been lying dormant for so long.

And clearly he had the power over her to take anything he wanted now.

“...Are you sure we’re still talking about me?”

Silence. Aly had struck the right chord.

The silence seemed to only last for an hour or so before there was commotion in the hall beyond the doors that led to the broken escalator. Papyrus’ familiar scratchy voice stammered something quick and inaudible as multiple sets up of footsteps stomped up the nonfunctional metal staircase.

The door flung open as the familiar brunette stormed in, surveying the area until her eyes found their way to the opposite side of the room. Papyrus stumbled in behind her, guilt-ridden eye sockets shifting to Aly. He clearly made an attempt to accommodate Aly’s wishes to make her reunion with her sister a gradual one. Unfortunately, there was _nothing_ gradual about Mimi.

“Aly, I’m sorry she’s just—”

The sisters stood with time frozen between them for a moment before Aly cleared her throat to speak. “...Hey, sis.”

Mimi remained frozen with her eyes set on Aly, only occasionally taking trepid steps closer and closer. Aly averted her own eyes away, almost ashamed to be seen in her condition. And Mimi’s expression was just so… pained. Mimi stopped, her legs shaking as she began to buckle under the strain of emotion visibly washing over her from head to toe. Aly could already tell the tears wouldn’t be far behind.

Aly sighed, realizing Mimi wasn’t going to approach her any further if she didn’t verbally invite her. It was almost the same reaction as when Papyrus first found her too - her appearance must have been having this effect on everyone that laid eyes on her. “I, uh, wish you would have waited until I’ve had the chance to clean up…”

That did it.

Mimi immediately closed the rest of the distance and collided with Aly, disregarding her injuries completely and then apologizing when Aly let out a weakened groan. Papyrus took this as his cue to exit and give them their privacy. Part of Aly wished he would have stayed. Even now as Mimi’s arms were wrapped around her, she didn’t feel quite ready for this.

“Oh my god…” Mimi sobbed as she fell onto the bed. “I didn’t think I was going to see you again…”

Aly let out a raspy chuckle. “You really thought I was going to leave you…?”

Mimi’s eyes glistened with moisture as she forced a tiny smile in between her cries. It didn’t last for more than a second before falling again at just the mere sight of Aly’s appearance. Her wandering hands gingerly touched the scars around Aly’s bloodshot eye and traced them all the way down the side of her face. From there, Mimi examined the rest of Aly’s mangled body, torn and broken in every place. She opened her mouth to speak, but nothing made it past the hiccups and desperate breaths.

“You don’t have to say anything,” Aly assured Mimi as she brought her own trembling arms up to embrace her sister. She ran the fingers on her good hand through Mimi’s knotted brown hair, but stopped when they grazed light purple spots on her neck. Bruises.

Aly pulled away from Mimi to examine it. “Mimi, what—”

“It’s nothing.” Mimi tried to pull Aly back in.

Aly refused, her brow furrowing. “Who did that to you…?”

Somehow, Mimi’s shifting glance was the only answer Aly needed to confirm the worst. However, that didn’t stop Gaster from also including insensitive input.

**_You don’t remember, do you?_ **

She didn’t. Aly couldn’t recall anything prior to finding herself in the Void again. But…

“It was me...”

Mimi shook her head as furiously as she could within the limits of her injured neck. “No, it wasn’t!” She grabbed Aly gently by the shoulders and stared at her with fervid desperation. “It was Gaster. _It wasn’t you._ ”

Aly was still straining to remember. “Th-that doesn’t make sense…”

“Aly, tell me what happened to you.”

 **_Tell her nothing,_ ** Gaster chimed in.

Aly was so distracted by his voice that she couldn’t help but fumble over broken strings of words as she failed to give Mimi anything remotely resembling an answer.

Sure enough, Mimi was insistent. “You’re safe now. I promise you can talk to me.”

**_You won’t._ **

The back and forth was making Aly’s head spin. She pressed the heels of her palms against her eyes from the physical pain of both Mimi’s and Gaster’s voices berating her at once.

However, one thing was clear: she _wasn’t_ safe. Aly could feel the tangibility of Gaster hanging onto her every word, even before they left her lips.

“...I’d rather not,” she finally responded to Mimi. Fear had gotten the best of her.

Mimi’s face dropped. “Aly.”

“Mimi, please—”

“Not this,” Mimi’s voice shook as she inhaled a deep breath of frustration before breathing it out from her mouth as calmly as she could manage. “Not now. Please not now.”

“You don’t even understand what you’re asking me to tell you.”

“But I want to!” Mimi was speaking with her hands now, gesturing large, frantic motions. “Sans told me the kinds of things that Gaster is capable of. But I need to hear it from _you,_ ” she stressed.

Aly grimaced. “Sans, huh?” How much did he know and how much was he telling everyone else?

Mimi nodded. “I didn’t want to believe that any monster down here could be capable of something so terrible since everyone has been so nice, but…” Her voice was shaking again - a mixture of anguish and sadness and heartache. “...I can’t deny the proof right in front of me. Aly, you look like… you look like you were on the verge of death...”

Aly opened her mouth to retort some remark about already dying several times, but caught herself before it slipped out. Dancing around the truth was much harder than she expected, especially when her sister’s pleading eyes continued to beg for answers.

“I-It wasn’t like that,” Aly eventually forced out. “Gaster, he…”

It was so hard to lie about this. So impossibly difficult.

But she _had_ to.

“He didn’t hurt me,” her voice involuntarily cracked towards the end. “Not… on purpose, at least.”

Mimi remained completely unconvinced.

“No, this is wrong,” Mimi exclaimed candidly as her face scrunched in suspicion. “There’s something you’re not telling me, Aly.”

Aly needed her sister to stop prying. “The only thing wrong is your intuition, sis. I’m back now, and I’m _fine._ I don’t want to talk about it anymore.”

Suddenly, she could feel it - the spike in Mimi’s impatience. It was sharp like toxic fumes that made the air stale. Perhaps Aly had tried to pull herself away too brusquely.

Mimi clenched her fists at her sides so tightly that her arms began to quiver. “I-I can’t believe you…”

“Mimi…”

Mimi reached her shaking hands up as if to grab Aly, but refrained from touching her at all.

“I… can’t… believe you…!” she hissed again through gritted teeth. The bomb had detonated. Mimi was shouting now, “You’re lying to me, Aly! You’re lying!”

Aly’s eyes widened at her sister’s dismay, but she had nothing left to say back. Mimi was right. She was lying, and she was lying poorly. Maybe on purpose? Aly couldn’t quite trust her own mind anymore.

Mimi was crying again, inconsolable wails ringling through the large room devoid of anything but the sparse furniture.

“You disappear for a week and then have absolutely nothing to say about it?!” Mimi’s outburst continued as she gestured to the entirety of Aly’s body again. “ _This_ wasn’t an accident. He _hurt_ you. He _wanted_ to. And you’re not fooling anybody - not even yourself!”

Aly couldn’t take it anymore. The weight of her guilt was becoming too much.

“...You’re out of control, Mimi. You need to leave.”

“You don’t care about anyone but yourself, Aly!  You’ve never let me in, not once!”

“Mimi—” Aly felt physically sick from hearing her sister this upset. And she knew there was nothing she could do that would replace telling Mimi the truth.

“Get. Out.”

The pain on Mimi’s face broke her. Aly turned away before she lost it completely.

Mimi let out one last frustrated scream before losing her will to argue for any longer. She didn’t even look back at Aly.

“...Nothing I do is ever going to get through to you…” Mimi mumbled dejectedly on her way to the exit. “...But I love you, Aly... and I’ll never stop fighting for you.”

Aly kept her head turned away from the door as she heard Mimi leave. As soon as Mimi’s footsteps down the escalator subsided, Aly could no longer hold her own tears back. She sobbed into her hands, still reeling at how impossible it was to lie to her sister and push her away so forcefully.

“You hurt her,” she scowled to Gaster past her tears. “Th-those bruises… You said you wouldn’t harm her.”

Gaster, who had been biding his time through the argument with Mimi, responded, **_I had no control over your actions at the time._ **

“Y-You liar,” Aly stumbled to her feet.

**_Perhaps you just need to come to terms with the fact that you have always been a danger to that girl._ **

“You don’t know anything about me.”

**_Neither does your sister, it seems._ **

“Shut up!” Aly shrieked as she staggered against the work table and knocked a stack of books to the ground. Gaster’s voice rattled inside her head as her heart began to beat irregularly. She could feel that hot energy constricting her soul again, but she fought it down as hard as she could.

_Not now. Not now._

**_You have no idea how to control this power_ ** , Gaster chuckled coldly. **_You need me._ **

“No!” Aly howled as she clutched her head, clawing at her hair because even the prospect of pulling it out was less painful than the ringing his voice induced inside her skull.

**_I don’t think you’re in any position to keep refusing._ **

The energy was starting to hurt again, festering in the pit of her soul like a virus. Aly was acutely aware of the differences now. This was how it felt when Gaster took control of it; his own brand of magic, just as Papyrus had his.

“Please…” Tears were still streaming down Aly’s cheeks. She couldn’t handle any of this right now, still too riled from the disaster her reunion with Mimi had turned out to be.

Gaster’s ruthless magic didn’t let up. **_Perhaps I miscalculated. Your will is much more fragile than I expected._ **

A pause.

**_Suppose your sister’s soul is stronger?_ **

_...No._

“No,” Aly immediately repeated her thoughts. “No no no no.” The word that Gaster seemed to hate so much. “That wasn’t the deal!”

**_With as resistant as you are, it seems this is all going to be wasted on you. It would be wiser to take this information and perfect the process next time, wouldn’t you agree?_ **

“You _just_ completed the experiment!” Aly’s booming voice echoed against the barren walls and called attention to his impatience. “You think this is _easy_ for me?”

_Anything. Say anything to keep Mimi out of this._

**_It could be if you were more naturally receptive to it._ **

“I-I’ll learn how to handle it—”

 **_You aren’t fooling anyone, my dear._ ** **Not even yourself,** **_as Mimi put it._ **

“You aren’t going to lay a hand on her!”

**_...Of course I won’t._ **

The toxic magic poured from Aly’s soul and shifted gravity around her again. It was violent this time, flinging her entire body against the nearest wall. Aly clamored as the bones in her shoulder popped under the sudden force. Her body was out of her control again, bent to the will of this invisible force fighting for its own permanence in its new host.

**_But you will._ **

“Y-You’re lying…” Aly choked. “The m-machine…”

The technology to fuse souls was gone - destroyed in the incident that Aly still could not explain. On top of that, was he insinuating that it was possible to _separate_ a fused soul again?

A bluff. This was all a bluff.

**_Machines can be rebuilt, my dear. And you possess the knowledge now to do it._ **

“N-No…” Aly hissed through her teeth as she struggled to stand. Her blood was boiling. “No!”

Alphys came crashing through the door, drawn by the noise of Aly’s screams and the physical struggle for control over her body.

“A-Aly…?!” Her eyes were wide with horror.

“Alphys…” Aly gasped out. “H-Help—”

The timid doctor shuffled over as quickly as she could, but stopped again with another shock-ridden stare. “Y-Y-Your eye!”

Aly’s eye was burning. And as she clutched it with her left hand, a blinding red glow reflected off the skin of her palm. Was it… _actually_ burning? It was impossible to focus on anything. Right now, she was just desperately trying to stave away the crippling magic.

“Please…” Aly pleaded. “I-I can’t c-control it…”

Luckily, Alphys seemed to already have a grasp on what Aly meant, even if Aly wasn’t even entirely sure herself.

“O-Okay… I n-need to get you downstairs,” Alphys stammered frantically. “To the lab.”

“Papyrus…” His name instinctively spilled from her lips. “I need Papyrus.”

“They’ve already t-taken the ferry back to Snowdin. I c-can try and call—”

“No time…” Aly cut her off, trying her best to focus on keeping the magic contained.

But Gaster wasn’t making it easy. **She** **_cannot help you, Aly. She couldn’t even help herself._ **

“S-Stop…” Aly was sure her perceptible banter with the voice in her head was only making Alphys even more concerned, but she couldn’t stay silent any longer.

 **_Do you really want to see how this plays out?_ ** Gaster prated, amused. **_Because I already know._ **

Another bluff. It had to be. But Aly was in yet another position where she would play into anything as long as it meant stopping the pain.

“Please…” she begged again under her breath. “J-Just… give me m-more time…”

 **_Very well._ ** Gaster’s grasp was subsiding again. **_But you know what is at stake now._ **

_Everything_ was at stake now that Mimi’s life was being threatened. Aly refused to let this happen to anyone else, especially her own blood - the only person she had left in this world.

The weight of her body under her own control was almost foreign each time it returned to her. She heaved forward, catching herself on the wall with one hand while Alphys caught the opposite side.

“I’m okay, I’m okay,” Aly exclaimed, mainly trying to convince herself.

“C-Can you walk?” Alphys helped Aly retain her balance.

Aly nodded. “I think so. Let’s just… get to the lab…”

 

After the longest, hottest shower Aly had ever taken, she met with Alphys in one of the examining rooms at the lowest level of the building. She had changed into a dark button-down shirt and jeans Mimi had left for her, supplied by the townspeople of Snowdin that had grown so fond of her sister.

It seemed that during their time in the Underground, Mimi had befriended every monster she met. Unfortunately, Aly couldn’t say the same. The only reason they probably tolerated her for this long was because she was related to the human they were all so taken with.

“Th-These are very serious injuries.” Alphys examined Aly’s wrists, viens still black underneath her swollen skin. She moved between studying each DT entry point individually. “It must have been excruciating.”

Aly nodded, but remained silent. She focused on the beads of water still dripping off of her damp hair from the shower.

Alphys hesitated. “C-Could you… could you tell me exactly what happened?”

Aly knew the answer to that, so she continued to hold her silence.

The lack of a reply didn’t seem to surprise the reptilian woman. “W-Well that’s alright. I think I know quite a bit already, actually.”

Alphys quickly scuttled to the desk on the other side of the room, grabbed a clipboard with a thick docket of notes attached, and made her way back.

“I… I gave up all of this research after moving to the Surface,” she explained. “Undyne and I focus primarily on human sciences now. B-But I did my fair share of experiments I wasn’t proud of down here…”

Aly looked on to the doctor’s notes, a combinations of typed paragraphs and notes scribbled in every margin. She couldn’t make much sense of them, but it seemed that Alphys knew precisely what pages she needed to skim through.

“Your left eye,” Alphys pointed to it without looking up from the clipboard. “That’s where we would administer _it_. Determination… i-is that correct?”

Aly’s brows furrowed. “You… You’ve done this?”

Alphys continued to circumvent her gaze around the room, but nodded sheepishly. “W-W-Well… to monsters. I-It w-wasn’t right, I know. But we were all a little too desperate for answers back in those days. Answers on how to break the barrier, a-and how to utilize human souls, and how to save ourselves from disappearing forever. We thought that the trait of Determination held the key to all of that. And I-I guess we were right about that in the end.”

Aly gathered in her head that Alphys’ experiments couldn’t possibly have been of the same caliber as what she had just gone though. Alphys was trying to help people, not selfishly gain something just for the sake of achieving it.

“Yours is… different than h-how I remember it to be, though. Maybe it’s just because this has never been performed on a human before.” Finally, she looked up at Aly. “But… whoever did this had very little concern for your physical being. Y-You shouldn’t have those… peculiar scars and…” Her eyes then trailed back to Aly’s arms. “The high dosage should have killed you very quickly.”

Another instance where Aly was inclined to instinctively mention the resets. However, the gnawing sense of dread in her chest returned; that throb that reminded her Gaster was listening.

“The one thing I’m most confused about though…” Alphys wavered. “Y-Your eye earlier… Humans shouldn’t be able to do that…”

“Do what?”

“Well, um… _glow._ ” Alphys scratched her chin, unsure of how to explain the phenomenon. “Surely you feel it.”

The burning sensation. Aly was unaware that there was also a physical component to it. “Yeah… I guess I do.”

“It’s an indication that your soul is reacting to magic. S-Something humans shouldn’t be capable of.”

“It’s… It’s unbearable sometimes. Sometimes it feels like my entire face is on fire.”

“This shouldn’t be possible,” Alphys kept repeating, mumbling scientific equations aloud as she began to bandage the wounds with new dressings, starting with the circular burns on Aly’s hands and moving up. “Humans can’t have magic, t-that’s a fact.”

Aly was apprehensive about all of the questions that this would open up.

And, sure enough, they began immediately, “S-So I g-guess the first thing I should really be asking is… _who_ did this to you?”

This question specifically was actually a bit surprising. Finally, someone Sans _hadn’t_ told about Gaster’s existence. However, if Sans didn’t tell her, then did that mean he was keeping it from her deliberately? Were Mimi and Papyrus the only others to know?

_Just play it safe for now._

Instead of trying to scramble for a lie, Aly relied on silence again.

After a while in the deafening quiet, Alphys chuckled under her breath. “You know, I always thought silence had its merits as an answer, too. M-Most times, people create their own answers just for the satisfaction of having one. And more often than not, those answers are better than the truth could ever be.”

“I-I hardly deserved to be called the Royal Scientist…” Alphys continued. “I came in as an intern and earned the King’s attention on the basis of a lie. The Determination experiments were catastrophic failures. E-Even the machines I built were based on blueprints left behind by my predecessor. It s-seemed that that DT extraction was the last thing he worked on here, too. I guess we were all so… so desperate. F-For a very long time.”

_Blueprints._

“...There was a Royal Scientist before you?”

_The machines._

“O-Oh yes, but it’s been centuries. Surely I’ve worked with him before, but I can’t even seem to recall his name. Something strange, maybe.”

The pieces fit together too clearly now as his name lingered at the edge of Aly’s tongue.

_W.D. Gaster._

However, Aly reminded herself that revealing this connection was a mistake. Instead, she tried to use this opportunity to find answers to different questions she had. “...Alphys, do you recall working with any human scientists by the names of Catherine and Derek when the barrier was opened?”

Alphys pursed her lips in thought and adjusted her glasses again. “We worked with a handful of human scientists that year, b-but those names don't ring a bell. D-Did you know them?”

**_She's forgotten them as well._ **

Aly shook her head, disappointed. “In a way, but… I guess it’s not important.”

The digression seemed to get Alphys off of Aly’s back about Gaster’s experiment… for now. It was bound to come up again, and she would need an answer next time.

As the last of Aly’s wounds were bandaged, Alphys moved to carefully cleaning the scars around her eye before patching that up as well. Considering her vision had still been absent from it since the first injection, the new obstruction barely affected her.

“I… I understand if you’re not ready to talk about it, Aly,” Alphys said. “I s-suppose we haven’t given you much time to digest this. M-Maybe we can perform the check-up tomorrow.”

“What are you going to do…?” Aly asked warily.

“I just want to run a few scans,” Alphys replied. “Standard stuff, really. J-Just to make sure your DT levels are stable now. I promise it won’t be that bad.”

Aly reluctantly nodded. “Okay… I think I can handle that.”

“Y-You can go back upstairs and sleep in my room if you’d like,” Alphys offered. “I know it’s nothing to brag about nowadays, but it’s probably a little more homey than down here.”

“No, you should take it. I’ll be fine.”

Alphys set her notes back down before shuffling to the door. “Remember, y-you’re safe now, Aly. I can’t imagine what you’ve been through, b-but we’re all here to help. Try to get some rest.”

Eventually, Alphys was gone and Aly was left with nothing but her thoughts, the incessant buzzing of the florescent lights…

And Gaster.

“You were the Royal Scientist.” Aly whispered forthright.

**_I’m impressed that you put it all together so quickly._ **

“Then how… how did it come to _this_?” Aly was referring to a lot of things. The Void, her parents, the experiment; so many events that she couldn’t get to coincide with a position so esteemed.

**_All the answers will come with time. Listen to the good Dr. Alphys and regain your strength; the tests continue tomorrow._ **

It didn’t matter what Alphys had in store, Aly knew she could handle it. Or… maybe she couldn’t.

Regardless, she didn’t want to think about any of that anymore. Aly rested her body back in the padded reclining examining chair and closed her eyes. It wasn’t as comfortable as a bed would have been, but it didn’t matter to her at this point.

According to Mimi, a week had passed. _Only_ a week. It felt like Aly had been trapped in complete darkness for months as she repeated the same nightmare over and over. Each reset was like waking up on a new day, with the same torture on the agenda. A true tomorrow never seemed to arrive in there.

The nightmare was far from over, Aly acknowledged that. But there was still solace knowing that when she woke up this time, it would finally be real.


	14. The Burden of Making Promises

**Summary for the Chapter:**

> Aly is beginning to understand more about Gaster, but less about his intentions. Alphys' tests yield fatal results.

**Notes for the Chapter:**

> Here it is! The truth is, we've been sitting on this chapter even though it was pretty much completed early on within these last three months. We hit a lot of blocks with little details that we were never able to flesh out until now. But, as always, thank you for your patience! Chapter 15 has been in the works for a while now too, so we'll try to get that posted as soon as we can.
> 
> In the meantime, don't forget to check out our [Tumblr](http://anundertaleoftwosisters.tumblr.com/)! We are still making Undertaken related art between each chapter.
> 
> Lastly, thank you for over 1100+ hits, something we never imagined when we started writing this story for fun last April. We are still determined as ever to finish this before we hit our one year anniversary, so we are looking forward to an exciting start to 2017!

Aly dreamt for the first night since everything began. But it wasn't her memories she was seeing this time. They weren’t familiar at all, but she _knew._

It was Gaster’s.

Like a movie, everything was happening in front of her with little regard as to whether she actually existed in this realm or not. The familiar lab in Hotland was bustling with life. And there he stood, at the center of it all. Tall and composed, wearing a lab coat and writing endless notes onto a clipboard with hands that were actually attached to his body. His skull was free of any cracks or abnormalities. For all intents and purposes he was… _whole_.

“Where are the reports from the latest test?” Gaster asked the room. He was speaking normally, every word clear without the use of his hands.

No one stopped moving for a second to acknowledge him, but a small, stuttering voice broke through the chaos.

“Th-They haven't come back yet, Doctor.” Alphys shuffled to his side. Her lab coat was buttoned up completely as she stood up straight, bright-eyed and youthful.

“We are running out of time.” Gaster was visibly frustrated, as if there was a sense of urgency that no one else in the lab seemed to share. “The King is already beginning to catch on to what we’re doing. If we don’t act soon, I’m afraid he won’t give us access to the human souls for very much longer. Our window is closing.”

“All of the simulations have been unsuccessful,” Alphys reminded him. “W-We still have no indication that any of these souls hold the strength to reset without the human they were once attached to controlling its save power. Even if fusing the individual souls’ abilities together on the scale that y-you’re theorizing were possible, i-it’s unlikely that you would be able to control it.”

“We need to move to a live subject.” Gaster handed over his clipboard to Alphys and directed his focus to the southernmost wall past several of his colleagues seated at their desks.

Alphys struggled to keep up with his pace as quickly as her short legs could carry her. “S-Sir, I hardly think we’re ready for—”

He stopped at the wall, shelves lined with familiar glass containers. Most were empty, but four cases at the very end housed four very differently colored souls, still pulsing with life.

Light blue, orange, dark blue, purple.

Four human souls. To Gaster, that was enough to accomplish whatever he had in mind. It _had_ to be enough.

“Where is he?”

Alphys averted her gaze from his direction as she attached the clipboard back to its home on the wall beside the shelves. “U-Unless you can unlock the reset abilities, you’ll only have one chance—”

“He volunteered, Alphys. He knows how important this is, but he also knows the risks.”

“...He’s your _son_.”

The emphasis on that word made Gaster waver. Only for a moment.

“Just bring him to me.”

***

Light began to fill the bedroom as the new day broke through the darkness of the agonizingly long night. Mimi laid completely still with her face turned to the wall, but the reality was that she hadn’t actually slept a wink. Meanwhile, Sans lounged on top of the covers beside her, clicking through his phone mindlessly for hours.

Mimi enjoyed his presence, but feigned sleep for as long as she could so that Sans didn’t have to worry about her. He had been doing enough of that lately.

However, the room was getting brighter by the minute now. No point in faking for any longer. She wanted to get as early of a start to the day as possible to get back to Aly.

“Sans…?” Mimi flipped her body around to face him.

Sans looked up from his phone and gave her a groggy, sleepless grin. “Mornin’, kiddo.”

Her face was inches away from his. She drank in his features; the pores of his skull, the spaces between the bones of his fingers. The way his ribs rose underneath his shirt every time he breathed in to exhale a tired sigh - a mannerism that he had seemed to pick up out of habit but wasn’t necessary for a skeleton.

Sans had spent every night by her side since she had asked him to. He was always awake before her, if he even slept at all, but no longer minded how she would just lie there beside him and get lost within herself as she stared. So Mimi had spent the last few mornings finding new little details to admire about Sans; little things to focus on and repel the constant anxiety that had made a home in her chest.

“Did you sleep okay?” Sans asked.

“It was fine,” Mimi lied.

“Think you’re ready to see your sister today?”

“I…” she hesitated. Of course she wanted to see Aly again. But the issue was if Aly wanted to see _her._

“It’s okay to say no, kid.”

“Th-That’s not it…” It was difficult to wrap her mind around everything that had happened. Before yesterday, she had given up hope on finding Aly. Now that she was found…

“I just… I want her to be ready too...”

“Al’s been texting me, she’s going to run the examination today,” Sans explained, glancing back at his phone and scrolling through the lengthy conversation he had been having with Alphys over the span of what appeared to be several hours. “I don’t know what she’ll find, if anything.”

“She wasn’t herself, Sans…” Some pieces still weren’t fitting together in Mimi’s head. “Sure, Aly was just as stubborn as always, but… there was something wrong. Something she’s not telling me.”

“Maybe she doesn’t have a choice.”

Mimi shot Sans a narrow look. “...I thought we were past hiding things, Sans. No secrets… remember?”

“We are, Mimi. It’s just…” Sans rubbed the heel of his palm against his eye socket, both in recollection and tiredness. “I don’t remember as much as I used to, I guess. So many iterations of the same thing - they tend to run together now.”

“Start with what you do remember, then.”

He sighed before gathering a concise answer. “I remember a lot of failures. They were starting to weigh down on him. Gaster, I mean. ...It consumed him eventually.”

“Do you think he failed with Aly too?”

“Kid, I don’t think she’d be alive if he did.”

“...What does that mean…?”

“Heh, that’s the million dollar question, isn’t it?” Sans put his phone down and turned his body to face Mimi as well. “We’ll get to the bottom of this and we’ll get your sister back to normal. But for now, Alphys asked that we refrain from coming back to the lab. She’ll send Aly this way once they’re done. Wants to avoid anymore, uh… emotional disruptions.”

Sans’ last statement hurt, maybe more than it should have. Was she a ‘disruption’? It was probably accurate, considering what happened between her and Aly yesterday. However, she regretted every moment of it. She said things she didn’t mean and could see now that it was wrong of her to push Aly so quickly after she had just been found.

She had to make it right today.

“Sans…” Mimi studied the shift in his expression when she called to him. “Can I ask you something else?”

“Anything.”

She had so many burning questions about too many subjects. Aly, and Gaster, and things she still couldn’t understand. But the truth was… she really just enjoyed hearing Sans’ voice.

“...Where does the light come from down here?”

“....What?”

“D-Down here. We’re underground, but…” Mimi wasn’t sure where her arbitrary question was going. “But it still becomes light in the morning and dark at night.”

Sans chuckled lightly, also acknowledging the irrelevance of the question. “Magic.”

“Really?”

He nodded. “Same magic that every monster has coursing through them. The kind that gives them life.” He tapped lightly within the gap of the ulna and radius bones of his forearm. “Holds their bones together.”

Mimi focused on the flickering lights resting in Sans’ dark eye sockets. The white flames that lit his malleable skull with emotion as he spoke.

She could stare into them all day.

“I wonder… if having magic like that could have helped me protect her that night...”

“Trust me, kid… you don’t want this.” Sans sat up, joints in between his bones popping back into place.  “Besides, you humans have your own abilities.”

Mimi cocked her head. “What do you mean?”

“Let me show you.”

Mimi hesitated as Sans hovered one of his hands over her torso. She wasn’t sure how to describe the sensation that came next; a warmth resonating from the tips of his fingers and bouncing off of her skin. One of his eyes reacted in tandem with the feeling, gently flickering a pale blue under his furrowed brow line as he focused on steadying his hand.

There was a light pull in Mimi’s chest. It only lasted a split second before the results of it was glowing right in front of her.

“W-What—”

“This is your soul,” Sans explained, examining the vibrant cyan light emitting from it. “And it’s powerful, stronger than mine or any other monster’s.”

Sans reached his other palm up as if to grasp it with both hands, but stopped just short of making physical contact. “Promise me you’ll keep it safe, Mimi. It’s worth protecting.”

Mimi nodded a silent agreement, still captivated by the sight. There was a certain ethereal quality to seeing her soul exist outside of her body for the first time. It was the culmination of everything she was. Something so small and so delicate, yet so _powerful_... as Sans had put it.

“It… It’s beautiful…”

Sans looked up at her as the glow in his eye subsided and the light of her soul began to disperse with it.

“Yeah…” his voice cracked as their gazes met. “I think so too.”

***

Aly didn't realize before now that her hands wouldn't stop shaking. She could feel them trembling in her sleep, a nervous tick forming regardless of how much she tried to calm herself.

Alphys’ presence made her more uneasy after seeing her in Gaster’s memories. Perhaps Alphys couldn't remember, but that didn't change the fact that she had worked so closely with him when this lab and the experiments it conducted were in full swing.

Time was a concept that slipped more and more away from Aly with each passing minute. All she knew is that she must have been sleeping for a while. Alphys came into the room, already dressed in her labcoat over a new graphic tee, a styrofoam cup of freshly heated instant noodles in hand. When asked if she was hungry, Aly declined. It was strange. Somehow, even after so long without nourishment, her body continued to carry on as best as it could beyond its new developments.

The machines in the examining room were almost identical to the ones Aly had experienced before in the Void, but most sat idle this time. Alphys checked Aly’s uneven heartbeat through a stethoscope, nearly convincing Aly that she was a real doctor and not just a title that came with the experience of working under the former Royal Scientist.

“H-Has your heartbeat always been irregular?”

“I think so,” Aly lied. The truth was that this was a direct effect of the experiment.

Alphys nodded hesitantly, putting down the stethoscope and replacing it with a thin needle attached to a long tube that filtered into a plastic container. “I need to take a sample to measure your DT levels next.”

Aly’s muscles tensed at the sight of the needle. Her fingers instinctively locked around the arms of the chair. “...Alphys, I—”

“I-It’ll be quick,” Alphys read the worry turning into terror on Aly’s face.

_This is nothing_ , Aly tried to convince herself. _I’m safe._

But her mind wasn't letting her believe that. Her stomach churned and her veins ached at the mere thought of being prodded again. Something so small had so much power against her now.

_Don't let the fear control you._

_Don't let_ him _win._

“I'm fine,” Aly’s voice shook. “Go ahead.”

Alphys gently unraveled the bandages in the crook of Aly’s left arm. The skin around the joint was still black and swollen, making it nearly impossible to find a vein in the area the wasn't damaged.

The doctor’s hesitation didn't calm Aly’s nerves. In fact, the fear was beginning to suffocate her as she heaved for air.

“W-We don't have to do this today.”

“No,” Aly snapped. “Get it over with.”

“...I-Is there any way you could s-stop your arm from shaking?”

Again, Aly hadn’t even realized that the trembling hadn’t stopped at all. She didn’t know what to tell Alphys, because she couldn’t get it to stop.

**_Allow me._ **

Without her consent, Gaster was taking over again. It was still frightening how easy it was for him to do so. She could feel the vibrations in her soul as it pumped with his magic and distributed it through her body like a functioning organ. He wrapped around the muscles in her arms, constricting them until all movement ceased.

**_Let the good doctor do her job._ **

“Sorry…” Aly answered to both Alphys and Gaster simultaneously. Alphys thanked her and continued.

Once a live vein had presented itself in Aly’s arm, Alphys wasted no time threading the long tip of the needle through the bruised skin and into the source of Determination that had mixed with Aly’s bloodstream.

As red liquid began to slowly siphon from her body and through the winding plastic tube, Aly couldn’t bear to look at the needle. DT didn’t hurt nearly as much coming out as it did going in, but the fresh memory of it alone was making her sick. It was becoming more and more clear that she was never going to go back to who she once was. She would never be that strong again.

“Y-You know,” Alphys tried to engage in conversation as the liquid took it’s time filling the container. “I used to be afraid of needles, too. W-Well… I used to be afraid of everything.”

“How did you get over it?”

“Sometimes… you just have to.” Alphys laughed uneasily. “I-It seems impossible, but you realize that if you don’t, the culmination of all your fears is going to destroy you.”

Aly flinched at the notion. “...What if letting it destroy you is easier?”

“It’s always going to be easier, Aly. B-But there are people out there that need you beyond your fears…” Alphys paused. “Mimi needs you. I’ll admit that I-I don’t know much about you girls, but your absence and the fear that you’d never come back was literally k-killing her. Surely being alive, regardless of what you went through, is worth _that_ much.”

_It is._

Mimi was worth everything.

A sharp twinge of regret pierced Aly’s chest when she thought of her sister. She had been so incredibly selfish to push Mimi away like that. But the sooner this was over, the sooner she could see her again and beg for forgiveness.

_Get through this for her._

The small talk was working to keep Aly distracted.

“Did you come down here just for me, Alphys?”

The reptilian woman nodded as she retrieved the needle from Aly’s arm and capped the container filled with her blood. “Sans asked, and he and I go way back. The only downside is that the poor signal down here keeps me a l-little out of the loop with our work on the surface. B-But I’m sure Undyne has everything under control.”

“If your tests don’t come up with anything, will you be going home?”

Alphys nodded again, a little too enthusiastically this time. “When you get used to calling somewhere like the surface your home, coming back down here again can be a little difficult.”

Too many times had Aly taken her life up there for granted. All she wanted now was to go back, too.

“...Is there anything else?”

“T-There’s one last thing I need from you today.” Alphys sighed, setting down the collected sample and picking up a longer syringe that Aly hadn’t noticed before.  “I… I want to study how your soul reacts to DT.”

Aly froze.

“No.”

**_Show her._ ** Gaster was almost sneering, Aly could feel it.

“...Please don’t make me do that.”

“Aly, I’m s-sorry, this is the m-most crucial part—”

**_They all need to see what you’re capable of, darling._ **

“I can’t—”

**_What_ ** **I’m** **_capable of._ **

Her body wasn’t hers again. Before she could even finish her last sentence, Aly could feel her limbs going numb with pins and needles that crept along her muscles. It was extending upwards, into her throat, pressing her larynx so she could no longer speak.

More and more, Gaster was learning how to push her out. He was finding her weaknesses.

_W-What are you doing?!_

Not that he could hear her thoughts anyway.

Alphys had noticed the sudden shift in Aly’s disposition. “A-Are you o-okay…?”

“Fine,” Aly spoke, but it wasn’t right. It was her voice, yet it wasn’t. “Just do it quickly, Alphys.”

_Stop._

Alphys wavered, but nodded sheepishly, taking advantage of Aly’s apparent willingness now. “Okay, i-if you could just lean back, I’ll need your eye…”

_Stop this._

Aly’s body was following the motions without resistance. She was losing.

_I just made it out._

A different needle with a different extract of DT was hovering closer and closer to her left eye. It was happening all over again. And, just like before, Aly was powerless to stop it.

Aly yelped as the thin tip nestled into her cornea. It was still so sensitive from before, but she knew the worst of it had yet to come.

“Bear with me,” Alphys repeated softly, flinching every time Aly convulsed under her hands. “I’m sorry, Aly. I-I’m sorry...”

Waiting for the inevitable was the most difficult part. It wouldn’t be long, but that didn’t stop Gaster from filling the few seconds of silence that Alphys no longer could with that echo of a voice that Aly hated so much.

**_She learned this procedure from me, you know._ **

_I don’t care._

**_You asked once before about it. Do you want to know why it’s done this way?_ **

_I don’t care._

**_Well, a brilliant human doctor once even referred to this method of destroying connections to the brain as_ ** **soul surgery.** **_We took a more literal approach to the term down here, discovering that the ability to inject Determination directly into the white matter of the brain through the eye socket was the fastest way to elicit a response from souls. So, rather than severing the transmitters to the prefrontal cortex as you humans were so foolishly doing, we were_ ** **enhancing** **_them to immeasurable levels._ **

_Why is he telling me all of this n—_

As if taking the verbal cue, Aly’s soul suddenly reacted to the familiarity of excess Determination. The burning sensation returned, numbing all of Aly’s senses of everything but pain.

Gaster’s voice continued beyond her screams. **_And thanks to my previous work on you, your soul has already reached its fullest potential. So the results of Alphys’ additional injection should be…_ **

Aly wailed as her soul forced its way from her chest without the use of separate magic to coax it out. After all, her body was producing its own magic - too much of it.

**_Very, very interesting._ **

It wasn’t becoming any easier to stomach what her soul looked like now. Alphys seemed to share that same sentiment when the sight of it left her mouth agape, at a loss for words.

“Th-th-this… I-I’ve never—”

“Is this… what you wanted... Alphys?” It wasn’t Aly’s voice in between gasps for air. It was, but it _wasn’t._

Alphys was still speechless, fumbling over noises that wouldn’t piece themselves into anything coherent.

The further the Determination welled inside of Aly, the harder it was becoming to stave off the magic again. And Gaster certainly wasn’t helping. In fact, he was welcoming it.

She couldn’t keep fighting.

“I-I can h-help you, Aly…” Alphys slowly began to back away, pawing for various components on the desk behind her. “Your s-soul is corrupted, b-but we can fix it somehow…”

“It doesn’t… need fixing...”

This wasn’t her voice. It wasn’t.

“...It needs to become stronger.”

...Was it?

Aly could feel her bones rattling inside her body as she stood up from the examining chair and took a step towards the reptilian monster cowering over the edge of her desk now. Whether this was Gaster’s doing or a jumpstart from the injection, the magic was building.

_Control it._

**_Let go._ **

“A-Aly just tell me what happened to you.” Alphys was becoming desperate, fear draining the color from her scales as her hands fumbled for a new syringe while she spoke.

Aly knew she had already lost.

So she fell into the same inevitable pattern of giving into what Gaster wanted.

She let go.

The energy inside of her erupted, ripping itself from her body with grotesque force. The invisible sensation of her skin flaying and burning away with the heat of this uncontainable magic that wasn’t truly hers.

Bones materialized under the ground beneath her and shot up in every direction, breaking glass, knocking down shelves, and one even piercing Alphys in the shoulder and knocking her to the ground.

The rest of the excess magic was taking a corporeal form in front of Aly; more bones snapping into place as this colossal mass formed in the space between her and Alphys. It began to take the shape of a gnarled bestial skull, perhaps some mythical hybrid between a dragon and a goat. Layers of peeling tissue and muscle wrapped around patches of its horns and jaw. From the cracks in the osseous bone and eye sockets oozed red liquid. And the sound… the gurgling screech it made as it emerged...

Whatever Aly’s soul had created through Gaster’s magic was abominable.

And the wild flames of light in its bleeding eyes were staring at Alphys.

The doctor’s eyes were frantic behind the glare of her crooked glasses as her entire body remained frozen in place.

“I-I-I… r-rememb-ber… now…” Alphys’ voice was almost lost beyond the trembling of her entire body as she gripped her injured shoulder.

All the while, Gaster’s laughed quaked through Aly’s head.

**_Remarkable! Your soul’s capabilities continue to surprise me, Aly. Perhaps our arrangement will work after all._ **

“H-He got t-to you t-t-too… J-Just like before…”

_Before?_

“Gaster,” Alphys exhaled through strained breath.

“Th-that’s right… That’s his n-name. How could I have forgotten…?”

**_And at last, she truly does remember._ **

“Tell me how to stop it!” Aly stuttered, unsure of when exactly she regained enough control to speak again.

The doctor shook her head in surrender. “Th-This is how it ended before, too… the whole lab… our friends… our colleagues…”

“Ended?” Aly asked desperately. “What ended?”

“W-Why did you come back…?” It was unclear if Alphys was speaking rhetorically, or if she was aware of Gaster’s presence there with them.

Nevertheless, he did not address her directly again.

**_I was trying to help them, Aly. All of them. But Alphys stood in my way; put her emotions before science. That's why we failed. And that’s why we will always fail as long as she is around._ **

Aly frantically tried to ignore the magic waiting to be released.

“Tell me what to do, Alphys! Please just help me—!”

**_Your soul can’t handle this combination of magic and Determination. You must release it._ **

“There are too many good things in this world, Aly. Wherever he is… whatever he’s planning… promise me you won’t let him destroy this. The world isn’t like it was when he was around. Th-This timeline… this place in our universe… there is nothing left to be done. W-We succeeded. We’re free…”

**_There’s_ ** **always** **_work to be done._ **

The scale of Gaster’s vision was becoming larger than Aly could sustain on her own. More and more, he asked of her. First it was freedom, then it was control, and now…

**_You have a choice to make right now, my dear. Either you keep fighting and end up like poor Dr. Alphys, or we continue to push the boundaries of the impossible… together._ **

Alphys had people that loved her. That cared about her. That were going to worry when she never came home. None of this meant anything to Gaster.

Aly couldn’t put Mimi through the same heartache, not after all she had already had to endure.

“I’m sorry.”

She made her choice long ago.

“Don’t let him destroy this.”

_I won’t._

“Don’t let him destroy _you_.”

_…_

Heat flooded the room as red magic pooled in the mouth of the floating beast skull and instantaneously shot a beam of fiery energy at unfathomable speeds towards Alphys. There was a roaring explosion, then a blinding light…

And then silence.

***

The shrill screams coming through the intercom made Alphys flinch every time.

“Doctor, the output levels are t-too high!”

In his frustration, Gaster had reverted back into his strange sign language, stringing broken words together as one hand signed in Alphys’ direction while the other kept steady on the control panel in front of him. **“Don’t stop the transmitter, Alphys. We’re almost there.”**

Alphys seemed to be fluent in translating his swift hand motions. “H-He’s going to die!”

**“He won’t. Keep an eye on his vitals.”**

“T-Th-They’re spiking, I don’t know how long his soul will be able to contain this amount of magical energy.”

**“If we stop it now, we could lose the human souls. Cross-streaming their energy makes them vulnerable. If one gives out, they all do. We cannot let that happen under any circumstances.”**

The screams continued over their strained conversation. The rest of the lab was dark, an eerie stillness thickening the air. Alphys and Gaster were the only ones remaining.

“D-Do you c-care about him at all, Dr. Gaster?”

**“What?”**

Alphys couldn’t even face him at this point. She kept her eyes low as her fists shook against the electric panel. “Y-You’re killing him, and the human souls are your biggest concern. N-Not your…”

Gaster glanced over at her, his expression daring her to finish the sentence at her own risk. She did not.

**“This is for the greater good of monsterkind, Alphys.”**

“...Greater good,” Alphys sighed. “Y-Yes, that’s right…”

Gaster, too, let out an exhausted sigh as he held down the button controlling the intercom into the next room where the periodic screams were coming from.

**“We’re nearly there. Just hang on a little longer, Sans.”**


	15. The Simplicity of Pretending

**Summary for the Chapter:**

> Time is passing, things are becoming normal again. However, there is a certain unease in accepting things as they are.

**Notes for the Chapter:**

> This chapter has actually been completed for quite some time now, but we held onto it hoping to add more. Instead, we've decided we are going to add two additional chapters to the story.
> 
> Also, from these sisters to you, Happy National Siblings Day!
> 
> Originally posted to [Tumblr](http://anundertaleoftwosisters.tumblr.com/).

Everyone had fallen into a pattern where time became irrelevant. A week had passed. Then another. Then maybe another, but Aly couldn’t be sure of the exact day anymore. What she did know was that, little by little, life was moving forward again. The bruises were lighter, the scars were fading, and her hands had finally stopped shaking.

Mimi had grown complacent, as if she were already forgetting. And Sans was there to replace the trauma with new memories that reminded her what it was like to smile again. Aly could see the two of them growing closer; the way Sans stared at her, or the way Mimi would shyly graze her skin against his bones. Sans was there for her when Aly couldn’t be.

In the days that went by, Papyrus tried to help Aly in the same ways. However, it was impossible to focus on anything but the extra voice echoing across the reverberations of her own words. She dreamt almost every night now. Sometimes they were residual memories, sometimes nightmares. Mimi had even caught Aly’s hands signing in Gaster’s strange language on some nights. However, Aly could tell that there was a reluctance that stopped Mimi from asking about it any further. Regardless of how hard they tried, the tension between them had not completely subsided.

Aly dreamt of his son - _sons_ \- and woke up to face them every day; Sans and Papyrus. Why wasn’t that obvious to her before...? Gaster rarely answered her questions about them, so she had learned to stop asking.

She dreamt of parallel universes where everything was the same, but little details weren’t quite right. Sometimes they were nightmares in which Mimi had taken her place.

She dreamt of lives she had never lived - including Gaster’s. The brilliant Royal Scientist that had put science above all else. Eventually he had lost everything to it, too.

...And she was starting to feel _bad_ for him.

Aly watched her dreams as if they were a television show. The more she saw, the more she found herself on his side. She wanted him to succeed. The good intentions were there, but had simply been lost somewhere along the way.

Her soul was almost yearning for these times that she hadn’t actually lived through - a feeling of nostalgia or fleeting deja vu that made her heart ache. Sometimes she would catch glimpses of her parents in these borrowed memories. Unfortunately, there was no easy way to explain these occurrences to Mimi, as much as she longed to share them. So Aly kept them stowed away in the back of her mind, locked tight in her own memories that she was just grateful to now have of them.

Though, these weren’t the only things that plagued her recently.

Aly, seated at the edge of Papyrus’ bed that she had hijacked for herself over the last couple of weeks, flipped through her father’s worn black journal that Gaster had given her. She had read every page multiple times, so much so that the edges of the paper were beginning to fray; the bindings on the book’s spine slowly coming undone.

Part of her still naively hoped that there was an answer within these pages - an answer to _anything._ But the entries ended just as abruptly as their parents’ existence.

 _Don’t look for us,_ the last entry read. It was in her mother’s handwriting, scrawled haphazardly on the same page that detailed their own experiments in soul fusion. _Don’t look for W.D. Gaster. You girls will have each other, and that will be enough._

But it was becoming more and more apparent to Aly that it was no longer enough. These pages had been rendered useless now that she had discovered their last message too late.

She unfolded a loose slip of paper tucked in the journal with rough sketches of her parents’ altered extraction machine. She looked at it often, but not _too_ often as to alert Gaster to the fact that she used to wonder if creating another could be used against him. Though he had nothing to worry about now; Aly thought about it less and less with each passing day, surrendering to the impossibility that it would be successful.

 **_Your mother and father were brilliant scientists,_ ** Gaster chimed in regardless. **_I don’t believe any of the Underground would have gotten by in those pivotal years without them._ **

“Didn’t get them very far,” Aly scoffed.

**_Perhaps not, but it brought you here. And I am forever grateful for that._ **

_Grateful?_ That wasn’t a sentiment she knew Gaster to be capable of. It didn’t fit the rest of his disposition, like the wrong piece of a puzzle forced into an incorrect spot.

“I’m glad one of us has benefited from this.”

Gaster was silent for a moment. His responses to Aly’s inherent sarcasm were always the same, so perhaps he was simply trying to find an alternative way to phrase it now.

To Aly’s surprise, he changed the subject completely. **_Tell me, do you feel any different since that night at the lab?_ **

“What?”

 **_That night_ ** , Gaster pressed. **_Describe to me how it felt when you killed her._ **

It took a while for Aly’s mind to escape that night. She remembered how the panic felt as her trembling hands texted rapid messages from Alphys’ phone.

 _Sending Aly your way,_ she messaged to Sans in Alphys’ stead. _Couldn’t find anything of importance during the exam. Everyone is expecting me back soon, so I’ll see you guys when you get back._

She even tried to message Undyne in order to cover all the bases - not that cellular signal to the Surface carried far enough. Regardless, it seemed to have bought her time. Just how much, she couldn’t be sure.

“It… it was unbearable,” Aly’s voice cracked as she answered Gaster. It was a sensation that she had never felt before; something deep in the pit of her soul that knotted her entire chest. “It was almost like suddenly forgetting how to breathe.”

 **_“It gets easier after the first one.”_ ** Those were Gaster’s words right after Aly had watched Alphys turn to dust before her eyes. _Easier_ , he said. Easier to watch someone die, or easier to be the hand that killed them?

Turns out... it was both.

The panic lingered through several sleepless nights after Aly had arrived back in Snowdin, reunited with Mimi and the brothers. In the first several hours back, she was determined to somehow gain the control to reset in order to save Alphys from that night, silently running through ideas in her mind about how to take that power from Gaster.

However, it was just as he said. It was getting easier - easier to detach herself. Easier to let Alphys go.

Easier to let herself go.

With Gaster’s guidance on how to deal with the weight of guilt and against what remained of her own moral fiber, Aly had kept herself… busy.

It was harmless at first. Moldsmals in the forest, with no concept of life or death. Aly reminded herself that it was like squashing insects on the surface. However, it began to escalate. Her soul was feeding off of her apathy. Taking the souls of monsters was quelling it; making it feel normal again. Surely there was a scientific explanation behind it that she simply did not understand. But Gaster was confident in it, and it _was_ working. So Aly owed it to Gaster to trust him with at least _this_ much.

**_My team and I spent a great deal of time researching the adverse effects of Determination in the humans that fell here before their deaths. It was a limited sample size, but there were indeed some patterns worth noting. Most who fell were innocent. However, some of them…_ **

“What are you trying to say…?”

 **_Do you still feel bad about what happened to Alphys?_ ** Gaster derailed her once again.

Aly nodded. Of course she still felt guilty. Even though monster deaths were much less jarring than she expected, it was still in her human nature to feel accountable for the choices she made that night.

However, time had begun to heal that wound faster than she could comprehend.

“I do, but… but I feel like I can live with it.” It was as if she could justify it now. After all, she was still here, Mimi was still safe, and they were both stronger for it.

**_What about killing those creatures in the forest?_ **

“It’s… easier now.” Aly grimaced. Why was she admitting these things?

“Does that make me a bad person…?”

**_Of course not, my dear._ **

...How could it not?

 **_This new soul is evolving; finally adapting to its host. And with each soul you take, we, too, become more in sync_ ** **.** **_How does that feel?_ **

That arbitrary question had been following her for so long. The more Gaster asked it, the more Aly could nearly convince herself that he cared.

It was different now. Aly had time to accept that they were one in the same; her soul was his. His language, his memories, his knowledge had all become hers. And the more she could detach herself from her own emotions, the more she could understand his.

“It feels right.”

**_Don’t you see what you’ve gained, Aly? It goes beyond sheer strength. You can finally preserve the lost memories of your parents. You’ve given Mimi the happiness of company she’s lacked. Your entire journey up to this point has had purpose._ **

Purpose. He was right, wasn’t he?

The understanding must have been hard-pressed into her expression. **_I knew we could make this work. You see the value in our arrangement now too, don’t you?_ **

As much as it pained Aly to admit it, she did. But how was she supposed to submit to this truth when she had spent so much of her energy up to this point fighting it?

“If this is how it’s going to be from now on, then I suppose I never had the choice, did I?”

 **_You still have a choice. Need I remind you that machines can be restored?_ ** Aly could feel the tips of her fingertips tingle against her parents’ blueprints from Gaster’s warning. **_It’s either you, or… someone else._ **

“No,” Aly said firmly, with a confidence that had been missing before. “We’re passed that, I promise. I choose this.”

 **_I need to know for sure,_ ** Gaster crowed. **_Prove it to me._ **

 ***

Mimi set four plates on the kitchen table, evenly spaced and delicately decorated with four sets of silverware. Meanwhile, Papyrus tended to multiple pots and pans simmering on the stove behind her.

“It smells delicious, Paps!” she called out, straightening every piece to obsessive perfection.

“It’s a very special day, right?” Papyrus replied.

Mimi nodded, a smile gently gracing her lips. “To think, we’ve lost track of time so much lately, I nearly forgot about it. I’m sure Aly has.”

“Well, surely a breakfast feast like this will remind her!”

Mimi giggled. “If it doesn’t, I don’t know what will.”

As the duo continued meal preparations in the kitchen, Sans appeared in the doorway, led by the invisible scent trails of food.

“This smells like your best work yet, Paps,” he grinned tiredly, with a hint of enthusiasm. “Must be a special occasion.”

“Good morning, Sans!” Mimi jumped up from her task and immediately greeted him in the doorway with a short, yet affectionate embrace.

Sans wrapped one arm around her, accustomed to this level of physical contact now. “Happy birthday, kid.”

Mimi’s heart fluttered under his touch. Her smile couldn’t help but widen.

“Is Aly still asleep?” she asked.

“Probably. Why don’t you go wake her up?” Sans said as he shuffled towards the pot of coffee sitting on the counter.

Mimi nodded. “Okay, I’ll be right back!”

 

As Mimi ascended the stairs and approached Papyrus’ bedroom door, the muffled sounds of Aly’s whispering voice grew louder. What started as only being able to hear a few words slowly turned into fuller phrases as Mimi took more steps closer.

“...can’t expect me to do that…”

A pause.

“...going to notice…”

_Who is she talking to…?_

As Mimi’s hand grazed the door, the conversation on the other side ceased.

_Strange._

Mimi tapped her knuckles lightly against the worn wood, but didn’t wait for a response before entering. As she stepped in, she spotted Aly sitting at the edge of the bed, fully dressed in one of Papyrus’ cropped shirts that fell loosely over Aly’s torso, his scarf, and a pair of rolled-up jeans. However, she also noticed that Aly was completely alone in the room.

“Morning, sis,” Mimi cooed quietly.

“Hey,” Aly responded even quieter.

“We… weren’t sure if you were awake yet.”

Aly nodded. “Couldn’t really get to sleep last night.”

Mimi swung around the bed and took a place on the edge of it right next to her sister. “Out of excitement for today, I hope!”

“...What?”

Mimi’s little grin faded with the confusion in Aly’s expression. She really didn’t remember.

“You know… that one day that comes around every year?”

It took Aly a second, but her tired eyes widened when she finally put the pieces together.

“I-It’s our birthday.”

“It’s our birthday!” Mimi parroted with cheerful inflection before scooping Aly into a hug. However, Aly did not reciprocate. Mimi tried to ignore it, only squeezing her tighter.

“I… I can’t believe I forgot.”

“Hey, no worries, sis!” Mimi bounced up from the bed and grabbed Aly’s hands to pull her up as well. “I know it’s hard to keep track of the days down here, but we’ve still got all day to celebrate!”

Aly flashed a hesitant smile from behind the scarf loosely wrapped around her neck. “I don’t know, Mimi--”

“You’re not going to mope around by yourself today,” Mimi exclaimed firmly. “We’re going to get out, go into town, and spend some time together.”

“Everyone in town hates me.”

“That’s not true!” ...Actually, it was a _little_ true. Some of the townsfolk had expressed their concern about previous events. They continued to bring up the times when Mimi was ill, and Aly’s inability to cope with it. Some noted seeing her alone deep within the forest. Others suggested she would… talk to herself.

None of them new Aly like she did, though. Whatever they thought they were observing just wasn’t true - she was sure of that.

...Mostly sure.

“Not everyone can make friends as easily as you do, Mimi.”

“You made friends all the time,” Mimi reminded her.

“It’s different this time.”

“You don’t give yourself enough credit, Aly.” Mimi turned to face her. “You are the most remarkable human being I have ever known. Life right now is… different. But _we’re_ the same.”

Aly grimaced, but remained silent.

Things had been difficult lately. Aly never completely recovered from whatever she had experienced with Gaster - something of which Mimi still had no answers about. Alphys had left them with inconclusive results, and Aly herself insisted that she was fine. But there was a lingering strain between them since Aly returned to Snowdin that first night; a tension that Mimi couldn’t correctly place. However, she made the conscious effort everyday to move forward. After all, _she_ was happy - Aly deserved the same.

“Papyrus made a killer breakfast, you’re going to love it.” Mimi shook off her reservations once again and forced a smile. “Do you remember when we were kids? All you wanted was breakfast for every meal.”

The memory was met with more silence at first, but there was a breakthrough when Aly let out a single, uneasy chuckle. “And you would pretend to want it too so that mom couldn’t refuse to keep making it.”

Mimi laughed. “I realized very quickly that my love for pancakes didn’t stretch as far as yours.”

For the first time in what felt like ages, Aly laughed. It was small, but it was genuine. However, it faded as quickly as it came.

“...Things were so simple back then.”

“They still can be, Aly.” Mimi took one of Aly’s hands in both of her own. It was stiff, reflecting the rest of her sister’s disposition.

“We could stay here… like this. With Sans and Papyrus. We can go back to the Surface with them and--”

Aly pulled her hand away. “This isn’t our life to live, Mimi.”

“But it _could_ be. We’ve found a home, Aly. A place where we’re welcome, and loved and…” Mimi paused. “And safe.”

She thought that maybe there might have been a better word to describe what she was feeling, since much of this journey into the Underground had not been particularly _safe_ for either of them. But Mimi believed, with all of her soul, that things could change.

“You don’t have to keep pushing us away anymore, or going off on your own, or feeling like you’re struggling with anything alone.”

Aly walked through the doorway of the bedroom and stopped at the edge of the railway.

“I’ll try, Mimi. For you.”

“Hey,” Mimi called to Aly. “To the ends of the earth, right…?”

Aly faltered, opening her mouth to elicit an instinctual response to the phrase. However, nothing came out before she shook her head and descended the stairs.

 

The meal, while cut short by a call for Papyrus’ assistance in Waterfall, managed to still be more memorable than Mimi could have ever hoped for. The past several birthdays had been spent on the road. Different city, different set of temporary acquaintances as she and Aly continued steadfast on the search for their parents. This was the first year the twins got to celebrate it in the comfort of a home, with people they cared about.

Papyrus had surprised them with a cake alongside all of their favorite breakfast items. Cake for breakfast… just like when they were kids. Sans took credit for the idea as his contribution to their modest celebration.

Mimi’s bright smile didn’t leave at any point during the conversation, and even coaxed out a couple more of those genuine little laughs from her sister.

For the first time, it really felt like they were healing.

After Papyrus’ abrupt exit, Mimi rinsed off the dishware one by one in the sink before handing it to Sans to dry. Aly had volunteered to bring cake to their friends in town - a surprising, yet thoughtful gesture. Mimi figured that maybe one good day was all Aly had been needing this entire time.

“Do you think Aly liked everything?” Mimi turned to Sans and handed him a fistful of silverware.

Sans shrugged nonchalantly. “I think her reaction was as good as we're gonna get.”

Mimi nodded, but quickly realized that Sans’ statement didn’t actually make her feel much better. “She hasn’t opened up to me about anything  yet…”

“I think it’s safe to say that she doesn’t plan to, kid.”

Mimi shot him a look. “That’s not true! We tell each other everything. It’s always been like that…”

Sans sighed, taking the next plate from Mimi’s hands and setting it down on the kitchen counter without drying it before turning to her.

“Mimi, do you honestly believe that Aly is the same person she was before you two fell down here?”

“Yes,” Mimi answered without a moment’s hesitation. “She’s my sister. My _twin_ sister. We have a connection that no one else can ever understand.” She pressed a soapy finger against her chest. “I _feel_ her, Sans. In my… in my soul. Like she’s a part of me. Things haven’t been the best between us lately, but… but she’s still Aly. And no matter what you or anyone else says, I know she hasn’t changed.”

Sans’ expression furrowed. The bones of his carpels scratched the rim of his eye socket as he rubbed the area in weary contemplation. He clearly did not agree with Mimi’s response. However, before he could say anything else, Mimi asserted herself again.

“That doesn’t mean she doesn’t need your help, Sans…”

Sans let out a surprised scoff. “Trust me kiddo, I’m the last person in this universe and the next that she would take advice from.”

“I know it doesn’t make sense. But you understand what happened to her better than I ever will, Sans. Whatever awful things Gaster put Aly through…” Mimi paused to compose herself. She could barely stand to think about it, let alone coming to the realization that Sans endured much of the same as well. “Her mind is in a place that I can no longer reach. But you can.”

“This is a mistake.” Sans leaned over the counter and buried his face in his hands. “All of this. You girls shouldn’t still be here. Alphys was supposed to take you-- No, you should’ve left a long time ago. We should have taken you back when you were sick.”

Pain hit Mimi’s heart under the weight of Sans’ words. “...And gone where…?”

“Home, Mimi.”

Mimi shuffled over to the kitchen table. She fell into the closest chair, still facing Sans as he stood frozen at the counter. “Do you… do you want to know what I wished for, Sans? For my birthday?”

“I don’t know what you’re--”

“I wished that we could stay here.” Mimi could feel herself fighting back tears now. “With you and Papyrus. And then when you went back to the Surface, I wished that we could stay with you there too. B-Because… Because…”

When she looked up at Sans and saw the flickering lights in his attentive eyes, she couldn’t hold the tears in anymore.

“Don’t you get it? This is home. _You_ are my home.”

Mimi’s sobs were the only thing to fill the deafening silence of the house for much longer than she was comfortable with. No matter how much time she had spent growing closer to Sans, letting her walls come down still left her feeling so vulnerable.

The silence between them lasted an eternity. She needed him to say something. _Anything._

“...Alright, kid. I’ll try to talk to Aly tomorrow. For you,” Sans finally replied. “Just… please don’t cry. Don’t let me be the jerk that made a girl cry on her birthday.”

Mimi couldn’t help but hiccup a laugh through her tears. “It’s still one of the best birthdays I’ve ever had.”

Sans ambled to the chair where Mimi was seated and rested his hand on her shoulder. “...I guess the only thing that could make it better is your birthday wish coming true, huh?”

“We don’t have anyone else, Sans...” Mimi sniffled with her face cupped in her hands. “No one but you and Papyrus...”

Mimi didn’t have to look up at him to feel the shift happening through his emotional barriers as well. He normally always acted so aloof, but surprised Mimi with how much he actually gave in to her requests.

“...Paps and I both want you here,” Sans admitted. “If only it could be that simple.”

“It can be.” The heightened sense of deja vu pulled at Mimi’s words. Sans and Aly had much more in common than either of them would admit. She wiped the tears from her eyes and rested her own hand on top of his.

“I already told you before, kid. As long as you’ll keep me around, I’m not… I’m not going anywhere.”

The butterflies returned. If only there were words to describe how much hearing that meant to her. And although she knew no amount of reassurance would ever suffice, Mimi wanted to at least try to return it to Sans. “Good, because neither am I.”


End file.
